Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

31 files changed, 5921 insertions, 0 deletions

diff --git a/tools/profiler/public/ChildProfilerController.h b/tools/profiler/public/ChildProfilerController.h
new file mode 100644
index 0000000000..8febc25b65
--- /dev/null
+++ b/tools/profiler/public/ChildProfilerController.h
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ChildProfilerController_h
+#define ChildProfilerController_h
+
+#include "base/process.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/ipc/ProtocolUtils.h"
+#include "mozilla/DataMutex.h"
+#include "mozilla/RefPtr.h"
+#include "nsISupportsImpl.h"
+#include "nsStringFwd.h"
+#include "ProfileAdditionalInformation.h"
+
+namespace mozilla {
+
+class ProfilerChild;
+class PProfilerChild;
+class PProfilerParent;
+
+// ChildProfilerController manages the setup and teardown of ProfilerChild.
+// It's used on the main thread.
+// It manages a background thread that ProfilerChild runs on.
+class ChildProfilerController final {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ChildProfilerController)
+
+#ifdef MOZ_GECKO_PROFILER
+  static already_AddRefed<ChildProfilerController> Create(
+      mozilla::ipc::Endpoint<PProfilerChild>&& aEndpoint);
+
+  [[nodiscard]] ProfileAndAdditionalInformation
+  GrabShutdownProfileAndShutdown();
+  void Shutdown();
+
+ private:
+  ChildProfilerController();
+  ~ChildProfilerController();
+  void Init(mozilla::ipc::Endpoint<PProfilerChild>&& aEndpoint);
+  void ShutdownAndMaybeGrabShutdownProfileFirst(
+      ProfileAndAdditionalInformation* aOutShutdownProfileInformation);
+
+  // Called on mThread:
+  void SetupProfilerChild(mozilla::ipc::Endpoint<PProfilerChild>&& aEndpoint);
+  void ShutdownProfilerChild(
+      ProfileAndAdditionalInformation* aOutShutdownProfileInformation);
+
+  RefPtr<ProfilerChild> mProfilerChild;  // only accessed on mThread
+  DataMutex<RefPtr<nsIThread>> mThread;
+#else
+  static already_AddRefed<ChildProfilerController> Create(
+      mozilla::ipc::Endpoint<PProfilerChild>&& aEndpoint) {
+    return nullptr;
+  }
+  [[nodiscard]] ProfileAndAdditionalInformation
+  GrabShutdownProfileAndShutdown() {
+    return ProfileAndAdditionalInformation(std::move(EmptyCString()));
+  }
+  void Shutdown() {}
+
+ private:
+  ~ChildProfilerController() {}
+#endif  // MOZ_GECKO_PROFILER
+};
+
+}  // namespace mozilla
+
+#endif  // ChildProfilerController_h
diff --git a/tools/profiler/public/GeckoProfiler.h b/tools/profiler/public/GeckoProfiler.h
new file mode 100644
index 0000000000..f7c045297e
--- /dev/null
+++ b/tools/profiler/public/GeckoProfiler.h
@@ -0,0 +1,435 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// The Gecko Profiler is an always-on profiler that takes fast and low overhead
+// samples of the program execution using only userspace functionality for
+// portability. The goal of this module is to provide performance data in a
+// generic cross-platform way without requiring custom tools or kernel support.
+//
+// Samples are collected to form a timeline with optional timeline event
+// (markers) used for filtering. The samples include both native stacks and
+// platform-independent "label stack" frames.
+
+#ifndef GeckoProfiler_h
+#define GeckoProfiler_h
+
+// Everything in here is also safe to include unconditionally, and only defines
+// empty macros if MOZ_GECKO_PROFILER is unset.
+// If your file only uses particular APIs (e.g., only markers), please consider
+// including only the needed headers instead of this one, to reduce compilation
+// dependencies.
+#include "BaseProfiler.h"
+#include "ProfileAdditionalInformation.h"
+#include "mozilla/ProfilerCounts.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/ProfilerMarkers.h"
+#include "mozilla/ProfilerState.h"
+#include "mozilla/ProfilerThreadSleep.h"
+#include "mozilla/ProfilerThreadState.h"
+#include "mozilla/ProgressLogger.h"
+#include "mozilla/Result.h"
+#include "mozilla/ResultVariant.h"
+
+#ifndef MOZ_GECKO_PROFILER
+
+#  include "mozilla/UniquePtr.h"
+
+// This file can be #included unconditionally. However, everything within this
+// file must be guarded by a #ifdef MOZ_GECKO_PROFILER, *except* for the
+// following macros and functions, which encapsulate the most common operations
+// and thus avoid the need for many #ifdefs.
+
+#  define PROFILER_REGISTER_THREAD(name)
+#  define PROFILER_UNREGISTER_THREAD()
+#  define AUTO_PROFILER_REGISTER_THREAD(name)
+
+#  define PROFILER_JS_INTERRUPT_CALLBACK()
+
+#  define PROFILER_SET_JS_CONTEXT(cx)
+#  define PROFILER_CLEAR_JS_CONTEXT()
+
+// Function stubs for when MOZ_GECKO_PROFILER is not defined.
+
+// This won't be used, it's just there to allow the empty definition of
+// `profiler_get_backtrace`.
+struct ProfilerBacktrace {};
+using UniqueProfilerBacktrace = mozilla::UniquePtr<ProfilerBacktrace>;
+
+// Get/Capture-backtrace functions can return nullptr or false, the result
+// should be fed to another empty macro or stub anyway.
+
+static inline UniqueProfilerBacktrace profiler_get_backtrace() {
+  return nullptr;
+}
+
+// This won't be used, it's just there to allow the empty definitions of
+// `profiler_capture_backtrace_into` and `profiler_capture_backtrace`.
+struct ProfileChunkedBuffer {};
+
+static inline bool profiler_capture_backtrace_into(
+    mozilla::ProfileChunkedBuffer& aChunkedBuffer,
+    mozilla::StackCaptureOptions aCaptureOptions) {
+  return false;
+}
+static inline mozilla::UniquePtr<mozilla::ProfileChunkedBuffer>
+profiler_capture_backtrace() {
+  return nullptr;
+}
+
+static inline void profiler_set_process_name(
+    const nsACString& aProcessName, const nsACString* aETLDplus1 = nullptr) {}
+
+static inline void profiler_received_exit_profile(
+    const nsACString& aExitProfile) {}
+
+static inline void profiler_register_page(uint64_t aTabID,
+                                          uint64_t aInnerWindowID,
+                                          const nsCString& aUrl,
+                                          uint64_t aEmbedderInnerWindowID,
+                                          bool aIsPrivateBrowsing) {}
+static inline void profiler_unregister_page(uint64_t aRegisteredInnerWindowID) {
+}
+
+static inline void GetProfilerEnvVarsForChildProcess(
+    std::function<void(const char* key, const char* value)>&& aSetEnv) {}
+
+static inline void profiler_record_wakeup_count(
+    const nsACString& aProcessType) {}
+
+#else  // !MOZ_GECKO_PROFILER
+
+#  include "js/ProfilingStack.h"
+#  include "mozilla/Assertions.h"
+#  include "mozilla/Atomics.h"
+#  include "mozilla/Attributes.h"
+#  include "mozilla/BaseProfilerRAIIMacro.h"
+#  include "mozilla/Maybe.h"
+#  include "mozilla/PowerOfTwo.h"
+#  include "mozilla/ThreadLocal.h"
+#  include "mozilla/TimeStamp.h"
+#  include "mozilla/UniquePtr.h"
+#  include "nscore.h"
+#  include "nsINamed.h"
+#  include "nsString.h"
+#  include "nsThreadUtils.h"
+
+#  include <functional>
+#  include <stdint.h>
+
+class ProfilerBacktrace;
+class ProfilerCodeAddressService;
+struct JSContext;
+
+namespace mozilla {
+class ProfileBufferControlledChunkManager;
+class ProfileChunkedBuffer;
+namespace baseprofiler {
+class SpliceableJSONWriter;
+}  // namespace baseprofiler
+}  // namespace mozilla
+class nsIURI;
+
+enum class ProfilerError {
+  IsInactive,
+  JsonGenerationFailed,
+};
+
+template <typename T>
+using ProfilerResult = mozilla::Result<T, ProfilerError>;
+
+//---------------------------------------------------------------------------
+// Give information to the profiler
+//---------------------------------------------------------------------------
+
+// Register/unregister threads with the profiler. Both functions operate the
+// same whether the profiler is active or inactive.
+#  define PROFILER_REGISTER_THREAD(name)         \
+    do {                                         \
+      char stackTop;                             \
+      profiler_register_thread(name, &stackTop); \
+    } while (0)
+#  define PROFILER_UNREGISTER_THREAD() profiler_unregister_thread()
+ProfilingStack* profiler_register_thread(const char* name, void* guessStackTop);
+void profiler_unregister_thread();
+
+// Registers a DOM Window (the JS global `window`) with the profiler. Each
+// Window _roughly_ corresponds to a single document loaded within a
+// browsing context. Both the Window Id and Browser Id are recorded to allow
+// correlating different Windows loaded within the same tab or frame element.
+//
+// We register pages for each navigations but we do not register
+// history.pushState or history.replaceState since they correspond to the same
+// Inner Window ID. When a browsing context is first loaded, the first url
+// loaded in it will be about:blank. Because of that, this call keeps the first
+// non-about:blank registration of window and discards the previous one.
+//
+//   "aTabID"                 is the BrowserId of that document belongs to.
+//                            That's used to determine the tab of that page.
+//   "aInnerWindowID"         is the ID of the `window` global object of that
+//                            document.
+//   "aUrl"                   is the URL of the page.
+//   "aEmbedderInnerWindowID" is the inner window id of embedder. It's used to
+//                            determine sub documents of a page.
+//   "aIsPrivateBrowsing"     is true if this browsing context happens in a
+//                            private browsing context.
+void profiler_register_page(uint64_t aTabID, uint64_t aInnerWindowID,
+                            const nsCString& aUrl,
+                            uint64_t aEmbedderInnerWindowID,
+                            bool aIsPrivateBrowsing);
+// Unregister page with the profiler.
+//
+// Take a Inner Window ID and unregister the page entry that has the same ID.
+void profiler_unregister_page(uint64_t aRegisteredInnerWindowID);
+
+// Remove all registered and unregistered pages in the profiler.
+void profiler_clear_all_pages();
+
+class BaseProfilerCount;
+void profiler_add_sampled_counter(BaseProfilerCount* aCounter);
+void profiler_remove_sampled_counter(BaseProfilerCount* aCounter);
+
+// Register and unregister a thread within a scope.
+#  define AUTO_PROFILER_REGISTER_THREAD(name) \
+    mozilla::AutoProfilerRegisterThread PROFILER_RAII(name)
+
+enum class SamplingState {
+  JustStopped,  // Sampling loop has just stopped without sampling, between the
+                // callback registration and now.
+  SamplingPaused,  // Profiler is active but sampling loop has gone through a
+                   // pause.
+  NoStackSamplingCompleted,  // A full sampling loop has completed in
+                             // no-stack-sampling mode.
+  SamplingCompleted          // A full sampling loop has completed.
+};
+
+using PostSamplingCallback = std::function<void(SamplingState)>;
+
+// Install a callback to be invoked at the end of the next sampling loop.
+// - `false` if profiler is not active, `aCallback` will stay untouched.
+// - `true` if `aCallback` was successfully moved-from into internal storage,
+//   and *will* be invoked at the end of the next sampling cycle. Note that this
+//   will happen on the Sampler thread, and will block further sampling, so
+//   please be mindful not to block for a long time (e.g., just dispatch a
+//   runnable to another thread.) Calling profiler functions from the callback
+//   is allowed.
+[[nodiscard]] bool profiler_callback_after_sampling(
+    PostSamplingCallback&& aCallback);
+
+// Called by the JSRuntime's operation callback. This is used to start profiling
+// on auxiliary threads. Operates the same whether the profiler is active or
+// not.
+#  define PROFILER_JS_INTERRUPT_CALLBACK() profiler_js_interrupt_callback()
+void profiler_js_interrupt_callback();
+
+// Set and clear the current thread's JSContext.
+#  define PROFILER_SET_JS_CONTEXT(cx) profiler_set_js_context(cx)
+#  define PROFILER_CLEAR_JS_CONTEXT() profiler_clear_js_context()
+void profiler_set_js_context(JSContext* aCx);
+void profiler_clear_js_context();
+
+//---------------------------------------------------------------------------
+// Get information from the profiler
+//---------------------------------------------------------------------------
+
+// Get the chunk manager used in the current profiling session, or null.
+mozilla::ProfileBufferControlledChunkManager*
+profiler_get_controlled_chunk_manager();
+
+// The number of milliseconds since the process started. Operates the same
+// whether the profiler is active or inactive.
+double profiler_time();
+
+// An object of this class is passed to profiler_suspend_and_sample_thread().
+// For each stack frame, one of the Collect methods will be called.
+class ProfilerStackCollector {
+ public:
+  // Some collectors need to worry about possibly overwriting previous
+  // generations of data. If that's not an issue, this can return Nothing,
+  // which is the default behaviour.
+  virtual mozilla::Maybe<uint64_t> SamplePositionInBuffer() {
+    return mozilla::Nothing();
+  }
+  virtual mozilla::Maybe<uint64_t> BufferRangeStart() {
+    return mozilla::Nothing();
+  }
+
+  // This method will be called once if the thread being suspended is the main
+  // thread. Default behaviour is to do nothing.
+  virtual void SetIsMainThread() {}
+
+  // WARNING: The target thread is suspended when the Collect methods are
+  // called. Do not try to allocate or acquire any locks, or you could
+  // deadlock. The target thread will have resumed by the time this function
+  // returns.
+
+  virtual void CollectNativeLeafAddr(void* aAddr) = 0;
+
+  virtual void CollectJitReturnAddr(void* aAddr) = 0;
+
+  virtual void CollectWasmFrame(const char* aLabel) = 0;
+
+  virtual void CollectProfilingStackFrame(
+      const js::ProfilingStackFrame& aFrame) = 0;
+};
+
+// This method suspends the thread identified by aThreadId, samples its
+// profiling stack, JS stack, and (optionally) native stack, passing the
+// collected frames into aCollector. aFeatures dictates which compiler features
+// are used. |Leaf| is the only relevant one.
+// Use `ProfilerThreadId{}` (unspecified) to sample the current thread.
+void profiler_suspend_and_sample_thread(ProfilerThreadId aThreadId,
+                                        uint32_t aFeatures,
+                                        ProfilerStackCollector& aCollector,
+                                        bool aSampleNative = true);
+
+struct ProfilerBacktraceDestructor {
+  void operator()(ProfilerBacktrace*);
+};
+
+using UniqueProfilerBacktrace =
+    mozilla::UniquePtr<ProfilerBacktrace, ProfilerBacktraceDestructor>;
+
+// Immediately capture the current thread's call stack, store it in the provided
+// buffer (usually to avoid allocations if you can construct the buffer on the
+// stack). Returns false if unsuccessful, or if the profiler is inactive.
+bool profiler_capture_backtrace_into(
+    mozilla::ProfileChunkedBuffer& aChunkedBuffer,
+    mozilla::StackCaptureOptions aCaptureOptions);
+
+// Immediately capture the current thread's call stack, and return it in a
+// ProfileChunkedBuffer (usually for later use in MarkerStack::TakeBacktrace()).
+// May be null if unsuccessful, or if the profiler is inactive.
+mozilla::UniquePtr<mozilla::ProfileChunkedBuffer> profiler_capture_backtrace();
+
+// Immediately capture the current thread's call stack, and return it in a
+// ProfilerBacktrace (usually for later use in marker function that take a
+// ProfilerBacktrace). May be null if unsuccessful, or if the profiler is
+// inactive.
+UniqueProfilerBacktrace profiler_get_backtrace();
+
+struct ProfilerStats {
+  unsigned n = 0;
+  double sum = 0;
+  double min = std::numeric_limits<double>::max();
+  double max = 0;
+  void Count(double v) {
+    ++n;
+    sum += v;
+    if (v < min) {
+      min = v;
+    }
+    if (v > max) {
+      max = v;
+    }
+  }
+};
+
+struct ProfilerBufferInfo {
+  // Index of the oldest entry.
+  uint64_t mRangeStart;
+  // Index of the newest entry.
+  uint64_t mRangeEnd;
+  // Buffer capacity in number of 8-byte entries.
+  uint32_t mEntryCount;
+  // Sampling stats: Interval between successive samplings.
+  ProfilerStats mIntervalsUs;
+  // Sampling stats: Total sampling duration. (Split detail below.)
+  ProfilerStats mOverheadsUs;
+  // Sampling stats: Time to acquire the lock before sampling.
+  ProfilerStats mLockingsUs;
+  // Sampling stats: Time to discard expired data.
+  ProfilerStats mCleaningsUs;
+  // Sampling stats: Time to collect counter data.
+  ProfilerStats mCountersUs;
+  // Sampling stats: Time to sample thread stacks.
+  ProfilerStats mThreadsUs;
+};
+
+// Get information about the current buffer status.
+// Returns Nothing() if the profiler is inactive.
+//
+// This information may be useful to a user-interface displaying the current
+// status of the profiler, allowing the user to get a sense for how fast the
+// buffer is being written to, and how much data is visible.
+mozilla::Maybe<ProfilerBufferInfo> profiler_get_buffer_info();
+
+// Record through glean how many times profiler_thread_wake has been
+// called.
+void profiler_record_wakeup_count(const nsACString& aProcessType);
+
+//---------------------------------------------------------------------------
+// Output profiles
+//---------------------------------------------------------------------------
+
+// Set a user-friendly process name, used in JSON stream.  Allows an optional
+// detailed name which may include private info (eTLD+1 in fission)
+void profiler_set_process_name(const nsACString& aProcessName,
+                               const nsACString* aETLDplus1 = nullptr);
+
+// Record an exit profile from a child process.
+void profiler_received_exit_profile(const nsACString& aExitProfile);
+
+// Get the profile encoded as a JSON string. A no-op (returning nullptr) if the
+// profiler is inactive.
+// If aIsShuttingDown is true, the current time is included as the process
+// shutdown time in the JSON's "meta" object.
+mozilla::UniquePtr<char[]> profiler_get_profile(double aSinceTime = 0,
+                                                bool aIsShuttingDown = false);
+
+// Write the profile for this process (excluding subprocesses) into aWriter.
+// Returns a failed result if the profiler is inactive.
+ProfilerResult<mozilla::ProfileGenerationAdditionalInformation>
+profiler_stream_json_for_this_process(
+    mozilla::baseprofiler::SpliceableJSONWriter& aWriter, double aSinceTime = 0,
+    bool aIsShuttingDown = false,
+    ProfilerCodeAddressService* aService = nullptr,
+    mozilla::ProgressLogger aProgressLogger = {});
+
+// Get the profile and write it into a file. A no-op if the profile is
+// inactive.
+//
+// This function is 'extern "C"' so that it is easily callable from a debugger
+// in a build without debugging information (a workaround for
+// http://llvm.org/bugs/show_bug.cgi?id=22211).
+extern "C" {
+void profiler_save_profile_to_file(const char* aFilename);
+}
+
+//---------------------------------------------------------------------------
+// RAII classes
+//---------------------------------------------------------------------------
+
+namespace mozilla {
+
+// Convenience class to register and unregister a thread with the profiler.
+// Needs to be the first object on the stack of the thread.
+class MOZ_RAII AutoProfilerRegisterThread final {
+ public:
+  explicit AutoProfilerRegisterThread(const char* aName) {
+    profiler_register_thread(aName, this);
+  }
+
+  ~AutoProfilerRegisterThread() { profiler_unregister_thread(); }
+
+ private:
+  AutoProfilerRegisterThread(const AutoProfilerRegisterThread&) = delete;
+  AutoProfilerRegisterThread& operator=(const AutoProfilerRegisterThread&) =
+      delete;
+};
+
+// Get the MOZ_PROFILER_STARTUP* environment variables that should be
+// supplied to a child process that is about to be launched, in order
+// to make that child process start with the same profiler settings as
+// in the current process.  The given function is invoked once for
+// each variable to be set.
+void GetProfilerEnvVarsForChildProcess(
+    std::function<void(const char* key, const char* value)>&& aSetEnv);
+
+}  // namespace mozilla
+
+#endif  // !MOZ_GECKO_PROFILER
+
+#endif  // GeckoProfiler_h
diff --git a/tools/profiler/public/GeckoProfilerReporter.h b/tools/profiler/public/GeckoProfilerReporter.h
new file mode 100644
index 0000000000..f5bf41f223
--- /dev/null
+++ b/tools/profiler/public/GeckoProfilerReporter.h
@@ -0,0 +1,26 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GeckoProfilerReporter_h
+#define GeckoProfilerReporter_h
+
+#include "nsIMemoryReporter.h"
+
+class GeckoProfilerReporter final : public nsIMemoryReporter {
+ public:
+  NS_DECL_ISUPPORTS
+
+  GeckoProfilerReporter() {}
+
+  NS_IMETHOD
+  CollectReports(nsIHandleReportCallback* aHandleReport, nsISupports* aData,
+                 bool aAnonymize) override;
+
+ private:
+  ~GeckoProfilerReporter() {}
+};
+
+#endif
diff --git a/tools/profiler/public/GeckoTraceEvent.h b/tools/profiler/public/GeckoTraceEvent.h
new file mode 100644
index 0000000000..75affaf9c8
--- /dev/null
+++ b/tools/profiler/public/GeckoTraceEvent.h
@@ -0,0 +1,1060 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file under third_party_mods/chromium or at:
+// http://src.chromium.org/svn/trunk/src/LICENSE
+
+#ifndef GECKO_TRACE_EVENT_H_
+#define GECKO_TRACE_EVENT_H_
+
+#include "MicroGeckoProfiler.h"
+
+// Extracted from Chromium's src/base/debug/trace_event.h, modified to talk to
+// the Gecko profiler.
+
+#if defined(RTC_DISABLE_TRACE_EVENTS)
+#  define RTC_TRACE_EVENTS_ENABLED 0
+#else
+#  define RTC_TRACE_EVENTS_ENABLED 1
+#endif
+
+// Type values for identifying types in the TraceValue union.
+#define TRACE_VALUE_TYPE_BOOL (static_cast<unsigned char>(1))
+#define TRACE_VALUE_TYPE_UINT (static_cast<unsigned char>(2))
+#define TRACE_VALUE_TYPE_INT (static_cast<unsigned char>(3))
+#define TRACE_VALUE_TYPE_DOUBLE (static_cast<unsigned char>(4))
+#define TRACE_VALUE_TYPE_POINTER (static_cast<unsigned char>(5))
+#define TRACE_VALUE_TYPE_STRING (static_cast<unsigned char>(6))
+#define TRACE_VALUE_TYPE_COPY_STRING (static_cast<unsigned char>(7))
+
+#if RTC_TRACE_EVENTS_ENABLED
+
+// This header is designed to give you trace_event macros without specifying
+// how the events actually get collected and stored. If you need to expose trace
+// event to some other universe, you can copy-and-paste this file,
+// implement the TRACE_EVENT_API macros, and do any other necessary fixup for
+// the target platform. The end result is that multiple libraries can funnel
+// events through to a shared trace event collector.
+
+// Trace events are for tracking application performance and resource usage.
+// Macros are provided to track:
+//    Begin and end of function calls
+//    Counters
+//
+// Events are issued against categories. Whereas RTC_LOG's
+// categories are statically defined, TRACE categories are created
+// implicitly with a string. For example:
+//   TRACE_EVENT_INSTANT0("MY_SUBSYSTEM", "SomeImportantEvent")
+//
+// Events can be INSTANT, or can be pairs of BEGIN and END in the same scope:
+//   TRACE_EVENT_BEGIN0("MY_SUBSYSTEM", "SomethingCostly")
+//   doSomethingCostly()
+//   TRACE_EVENT_END0("MY_SUBSYSTEM", "SomethingCostly")
+// Note: our tools can't always determine the correct BEGIN/END pairs unless
+// these are used in the same scope. Use ASYNC_BEGIN/ASYNC_END macros if you
+// need them to be in separate scopes.
+//
+// A common use case is to trace entire function scopes. This
+// issues a trace BEGIN and END automatically:
+//   void doSomethingCostly() {
+//     TRACE_EVENT0("MY_SUBSYSTEM", "doSomethingCostly");
+//     ...
+//   }
+//
+// Additional parameters can be associated with an event:
+//   void doSomethingCostly2(int howMuch) {
+//     TRACE_EVENT1("MY_SUBSYSTEM", "doSomethingCostly",
+//         "howMuch", howMuch);
+//     ...
+//   }
+//
+// The trace system will automatically add to this information the
+// current process id, thread id, and a timestamp in microseconds.
+//
+// To trace an asynchronous procedure such as an IPC send/receive, use
+// ASYNC_BEGIN and ASYNC_END:
+//   [single threaded sender code]
+//     static int send_count = 0;
+//     ++send_count;
+//     TRACE_EVENT_ASYNC_BEGIN0("ipc", "message", send_count);
+//     Send(new MyMessage(send_count));
+//   [receive code]
+//     void OnMyMessage(send_count) {
+//       TRACE_EVENT_ASYNC_END0("ipc", "message", send_count);
+//     }
+// The third parameter is a unique ID to match ASYNC_BEGIN/ASYNC_END pairs.
+// ASYNC_BEGIN and ASYNC_END can occur on any thread of any traced process.
+// Pointers can be used for the ID parameter, and they will be mangled
+// internally so that the same pointer on two different processes will not
+// match. For example:
+//   class MyTracedClass {
+//    public:
+//     MyTracedClass() {
+//       TRACE_EVENT_ASYNC_BEGIN0("category", "MyTracedClass", this);
+//     }
+//     ~MyTracedClass() {
+//       TRACE_EVENT_ASYNC_END0("category", "MyTracedClass", this);
+//     }
+//   }
+//
+// Trace event also supports counters, which is a way to track a quantity
+// as it varies over time. Counters are created with the following macro:
+//   TRACE_COUNTER1("MY_SUBSYSTEM", "myCounter", g_myCounterValue);
+//
+// Counters are process-specific. The macro itself can be issued from any
+// thread, however.
+//
+// Sometimes, you want to track two counters at once. You can do this with two
+// counter macros:
+//   TRACE_COUNTER1("MY_SUBSYSTEM", "myCounter0", g_myCounterValue[0]);
+//   TRACE_COUNTER1("MY_SUBSYSTEM", "myCounter1", g_myCounterValue[1]);
+// Or you can do it with a combined macro:
+//   TRACE_COUNTER2("MY_SUBSYSTEM", "myCounter",
+//       "bytesPinned", g_myCounterValue[0],
+//       "bytesAllocated", g_myCounterValue[1]);
+// This indicates to the tracing UI that these counters should be displayed
+// in a single graph, as a summed area chart.
+//
+// Since counters are in a global namespace, you may want to disembiguate with a
+// unique ID, by using the TRACE_COUNTER_ID* variations.
+//
+// By default, trace collection is compiled in, but turned off at runtime.
+// Collecting trace data is the responsibility of the embedding
+// application. In Chrome's case, navigating to about:tracing will turn on
+// tracing and display data collected across all active processes.
+//
+//
+// Memory scoping note:
+// Tracing copies the pointers, not the string content, of the strings passed
+// in for category, name, and arg_names.  Thus, the following code will
+// cause problems:
+//     char* str = strdup("impprtantName");
+//     TRACE_EVENT_INSTANT0("SUBSYSTEM", str);  // BAD!
+//     free(str);                   // Trace system now has dangling pointer
+//
+// To avoid this issue with the `name` and `arg_name` parameters, use the
+// TRACE_EVENT_COPY_XXX overloads of the macros at additional runtime overhead.
+// Notes: The category must always be in a long-lived char* (i.e. static const).
+//        The `arg_values`, when used, are always deep copied with the _COPY
+//        macros.
+//
+// When are string argument values copied:
+// const char* arg_values are only referenced by default:
+//     TRACE_EVENT1("category", "name",
+//                  "arg1", "literal string is only referenced");
+// Use TRACE_STR_COPY to force copying of a const char*:
+//     TRACE_EVENT1("category", "name",
+//                  "arg1", TRACE_STR_COPY("string will be copied"));
+// std::string arg_values are always copied:
+//     TRACE_EVENT1("category", "name",
+//                  "arg1", std::string("string will be copied"));
+//
+//
+// Thread Safety:
+// Thread safety is provided by methods defined in event_tracer.h. See the file
+// for details.
+
+// By default, const char* argument values are assumed to have long-lived scope
+// and will not be copied. Use this macro to force a const char* to be copied.
+#  define TRACE_STR_COPY(str) \
+    webrtc::trace_event_internal::TraceStringWithCopy(str)
+
+// This will mark the trace event as disabled by default. The user will need
+// to explicitly enable the event.
+#  define TRACE_DISABLED_BY_DEFAULT(name) "disabled-by-default-" name
+
+// By default, uint64 ID argument values are not mangled with the Process ID in
+// TRACE_EVENT_ASYNC macros. Use this macro to force Process ID mangling.
+#  define TRACE_ID_MANGLE(id) \
+    webrtc::trace_event_internal::TraceID::ForceMangle(id)
+
+// Records a pair of begin and end events called "name" for the current
+// scope, with 0, 1 or 2 associated arguments. If the category is not
+// enabled, then this does nothing.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+#  define TRACE_EVENT0(category, name) \
+    INTERNAL_TRACE_EVENT_ADD_SCOPED(category, name)
+#  define TRACE_EVENT1(category, name, arg1_name, arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD_SCOPED(category, name, arg1_name, arg1_val)
+#  define TRACE_EVENT2(category, name, arg1_name, arg1_val, arg2_name,   \
+                       arg2_val)                                         \
+    INTERNAL_TRACE_EVENT_ADD_SCOPED(category, name, arg1_name, arg1_val, \
+                                    arg2_name, arg2_val)
+
+// Records a single event called "name" immediately, with 0, 1 or 2
+// associated arguments. If the category is not enabled, then this
+// does nothing.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+#  define TRACE_EVENT_INSTANT0(category, name)                          \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category, name, \
+                             TRACE_EVENT_FLAG_NONE)
+#  define TRACE_EVENT_INSTANT1(category, name, arg1_name, arg1_val)     \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category, name, \
+                             TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
+#  define TRACE_EVENT_INSTANT2(category, name, arg1_name, arg1_val, arg2_name, \
+                               arg2_val)                                       \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category, name,        \
+                             TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val,       \
+                             arg2_name, arg2_val)
+#  define TRACE_EVENT_COPY_INSTANT0(category, name)                     \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category, name, \
+                             TRACE_EVENT_FLAG_COPY)
+#  define TRACE_EVENT_COPY_INSTANT1(category, name, arg1_name, arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category, name,  \
+                             TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val)
+#  define TRACE_EVENT_COPY_INSTANT2(category, name, arg1_name, arg1_val, \
+                                    arg2_name, arg2_val)                 \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category, name,  \
+                             TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, \
+                             arg2_name, arg2_val)
+
+// Records a single BEGIN event called "name" immediately, with 0, 1 or 2
+// associated arguments. If the category is not enabled, then this
+// does nothing.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+#  define TRACE_EVENT_BEGIN0(category, name)                          \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category, name, \
+                             TRACE_EVENT_FLAG_NONE)
+#  define TRACE_EVENT_BEGIN1(category, name, arg1_name, arg1_val)     \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category, name, \
+                             TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
+#  define TRACE_EVENT_BEGIN2(category, name, arg1_name, arg1_val, arg2_name, \
+                             arg2_val)                                       \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category, name,        \
+                             TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val,     \
+                             arg2_name, arg2_val)
+#  define TRACE_EVENT_COPY_BEGIN0(category, name)                     \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category, name, \
+                             TRACE_EVENT_FLAG_COPY)
+#  define TRACE_EVENT_COPY_BEGIN1(category, name, arg1_name, arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category, name,  \
+                             TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val)
+#  define TRACE_EVENT_COPY_BEGIN2(category, name, arg1_name, arg1_val,   \
+                                  arg2_name, arg2_val)                   \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category, name,    \
+                             TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, \
+                             arg2_name, arg2_val)
+
+// Records a single END event for "name" immediately. If the category
+// is not enabled, then this does nothing.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+#  define TRACE_EVENT_END0(category, name)                          \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category, name, \
+                             TRACE_EVENT_FLAG_NONE)
+#  define TRACE_EVENT_END1(category, name, arg1_name, arg1_val)     \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category, name, \
+                             TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
+#  define TRACE_EVENT_END2(category, name, arg1_name, arg1_val, arg2_name, \
+                           arg2_val)                                       \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category, name,        \
+                             TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val,   \
+                             arg2_name, arg2_val)
+#  define TRACE_EVENT_COPY_END0(category, name)                     \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category, name, \
+                             TRACE_EVENT_FLAG_COPY)
+#  define TRACE_EVENT_COPY_END1(category, name, arg1_name, arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category, name,  \
+                             TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val)
+#  define TRACE_EVENT_COPY_END2(category, name, arg1_name, arg1_val,     \
+                                arg2_name, arg2_val)                     \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category, name,      \
+                             TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, \
+                             arg2_name, arg2_val)
+
+// Records the value of a counter called "name" immediately. Value
+// must be representable as a 32 bit integer.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+#  define TRACE_COUNTER1(category, name, value)                         \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_COUNTER, category, name, \
+                             TRACE_EVENT_FLAG_NONE, "value",            \
+                             static_cast<int>(value))
+#  define TRACE_COPY_COUNTER1(category, name, value)                    \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_COUNTER, category, name, \
+                             TRACE_EVENT_FLAG_COPY, "value",            \
+                             static_cast<int>(value))
+
+// Records the values of a multi-parted counter called "name" immediately.
+// The UI will treat value1 and value2 as parts of a whole, displaying their
+// values as a stacked-bar chart.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+#  define TRACE_COUNTER2(category, name, value1_name, value1_val, value2_name, \
+                         value2_val)                                           \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_COUNTER, category, name,        \
+                             TRACE_EVENT_FLAG_NONE, value1_name,               \
+                             static_cast<int>(value1_val), value2_name,        \
+                             static_cast<int>(value2_val))
+#  define TRACE_COPY_COUNTER2(category, name, value1_name, value1_val,  \
+                              value2_name, value2_val)                  \
+    INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_COUNTER, category, name, \
+                             TRACE_EVENT_FLAG_COPY, value1_name,        \
+                             static_cast<int>(value1_val), value2_name, \
+                             static_cast<int>(value2_val))
+
+// Records the value of a counter called "name" immediately. Value
+// must be representable as a 32 bit integer.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+// - `id` is used to disambiguate counters with the same name. It must either
+//   be a pointer or an integer value up to 64 bits. If it's a pointer, the bits
+//   will be xored with a hash of the process ID so that the same pointer on
+//   two different processes will not collide.
+#  define TRACE_COUNTER_ID1(category, name, id, value)                         \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_COUNTER, category,      \
+                                     name, id, TRACE_EVENT_FLAG_NONE, "value", \
+                                     static_cast<int>(value))
+#  define TRACE_COPY_COUNTER_ID1(category, name, id, value)                    \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_COUNTER, category,      \
+                                     name, id, TRACE_EVENT_FLAG_COPY, "value", \
+                                     static_cast<int>(value))
+
+// Records the values of a multi-parted counter called "name" immediately.
+// The UI will treat value1 and value2 as parts of a whole, displaying their
+// values as a stacked-bar chart.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+// - `id` is used to disambiguate counters with the same name. It must either
+//   be a pointer or an integer value up to 64 bits. If it's a pointer, the bits
+//   will be xored with a hash of the process ID so that the same pointer on
+//   two different processes will not collide.
+#  define TRACE_COUNTER_ID2(category, name, id, value1_name, value1_val,      \
+                            value2_name, value2_val)                          \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                         \
+        TRACE_EVENT_PHASE_COUNTER, category, name, id, TRACE_EVENT_FLAG_NONE, \
+        value1_name, static_cast<int>(value1_val), value2_name,               \
+        static_cast<int>(value2_val))
+#  define TRACE_COPY_COUNTER_ID2(category, name, id, value1_name, value1_val, \
+                                 value2_name, value2_val)                     \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                         \
+        TRACE_EVENT_PHASE_COUNTER, category, name, id, TRACE_EVENT_FLAG_COPY, \
+        value1_name, static_cast<int>(value1_val), value2_name,               \
+        static_cast<int>(value2_val))
+
+// Records a single ASYNC_BEGIN event called "name" immediately, with 0, 1 or 2
+// associated arguments. If the category is not enabled, then this
+// does nothing.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+// - `id` is used to match the ASYNC_BEGIN event with the ASYNC_END event. ASYNC
+//   events are considered to match if their category, name and id values all
+//   match. `id` must either be a pointer or an integer value up to 64 bits. If
+//   it's a pointer, the bits will be xored with a hash of the process ID so
+//   that the same pointer on two different processes will not collide.
+// An asynchronous operation can consist of multiple phases. The first phase is
+// defined by the ASYNC_BEGIN calls. Additional phases can be defined using the
+// ASYNC_STEP macros. When the operation completes, call ASYNC_END.
+// An ASYNC trace typically occur on a single thread (if not, they will only be
+// drawn on the thread defined in the ASYNC_BEGIN event), but all events in that
+// operation must use the same `name` and `id`. Each event can have its own
+// args.
+#  define TRACE_EVENT_ASYNC_BEGIN0(category, name, id)                        \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE)
+#  define TRACE_EVENT_ASYNC_BEGIN1(category, name, id, arg1_name, arg1_val)   \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE,         \
+                                     arg1_name, arg1_val)
+#  define TRACE_EVENT_ASYNC_BEGIN2(category, name, id, arg1_name, arg1_val,   \
+                                   arg2_name, arg2_val)                       \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE,         \
+                                     arg1_name, arg1_val, arg2_name, arg2_val)
+#  define TRACE_EVENT_COPY_ASYNC_BEGIN0(category, name, id)                   \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_COPY)
+#  define TRACE_EVENT_COPY_ASYNC_BEGIN1(category, name, id, arg1_name,        \
+                                        arg1_val)                             \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_COPY,         \
+                                     arg1_name, arg1_val)
+#  define TRACE_EVENT_COPY_ASYNC_BEGIN2(category, name, id, arg1_name,        \
+                                        arg1_val, arg2_name, arg2_val)        \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_COPY,         \
+                                     arg1_name, arg1_val, arg2_name, arg2_val)
+
+// Records a single ASYNC_STEP event for `step` immediately. If the category
+// is not enabled, then this does nothing. The `name` and `id` must match the
+// ASYNC_BEGIN event above. The `step` param identifies this step within the
+// async event. This should be called at the beginning of the next phase of an
+// asynchronous operation.
+#  define TRACE_EVENT_ASYNC_STEP0(category, name, id, step)                   \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_STEP, category,  \
+                                     name, id, TRACE_EVENT_FLAG_NONE, "step", \
+                                     step)
+#  define TRACE_EVENT_ASYNC_STEP1(category, name, id, step, arg1_name,        \
+                                  arg1_val)                                   \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_STEP, category,  \
+                                     name, id, TRACE_EVENT_FLAG_NONE, "step", \
+                                     step, arg1_name, arg1_val)
+#  define TRACE_EVENT_COPY_ASYNC_STEP0(category, name, id, step)              \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_STEP, category,  \
+                                     name, id, TRACE_EVENT_FLAG_COPY, "step", \
+                                     step)
+#  define TRACE_EVENT_COPY_ASYNC_STEP1(category, name, id, step, arg1_name,   \
+                                       arg1_val)                              \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_STEP, category,  \
+                                     name, id, TRACE_EVENT_FLAG_COPY, "step", \
+                                     step, arg1_name, arg1_val)
+
+// Records a single ASYNC_END event for "name" immediately. If the category
+// is not enabled, then this does nothing.
+#  define TRACE_EVENT_ASYNC_END0(category, name, id)                        \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_END, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE)
+#  define TRACE_EVENT_ASYNC_END1(category, name, id, arg1_name, arg1_val)   \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_END, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE,       \
+                                     arg1_name, arg1_val)
+#  define TRACE_EVENT_ASYNC_END2(category, name, id, arg1_name, arg1_val,   \
+                                 arg2_name, arg2_val)                       \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_END, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE,       \
+                                     arg1_name, arg1_val, arg2_name, arg2_val)
+#  define TRACE_EVENT_COPY_ASYNC_END0(category, name, id)                   \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_END, category, \
+                                     name, id, TRACE_EVENT_FLAG_COPY)
+#  define TRACE_EVENT_COPY_ASYNC_END1(category, name, id, arg1_name, arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_END, category,    \
+                                     name, id, TRACE_EVENT_FLAG_COPY,          \
+                                     arg1_name, arg1_val)
+#  define TRACE_EVENT_COPY_ASYNC_END2(category, name, id, arg1_name, arg1_val, \
+                                      arg2_name, arg2_val)                     \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_END, category,    \
+                                     name, id, TRACE_EVENT_FLAG_COPY,          \
+                                     arg1_name, arg1_val, arg2_name, arg2_val)
+
+// Records a single FLOW_BEGIN event called "name" immediately, with 0, 1 or 2
+// associated arguments. If the category is not enabled, then this
+// does nothing.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+// - `id` is used to match the FLOW_BEGIN event with the FLOW_END event. FLOW
+//   events are considered to match if their category, name and id values all
+//   match. `id` must either be a pointer or an integer value up to 64 bits. If
+//   it's a pointer, the bits will be xored with a hash of the process ID so
+//   that the same pointer on two different processes will not collide.
+// FLOW events are different from ASYNC events in how they are drawn by the
+// tracing UI. A FLOW defines asynchronous data flow, such as posting a task
+// (FLOW_BEGIN) and later executing that task (FLOW_END). Expect FLOWs to be
+// drawn as lines or arrows from FLOW_BEGIN scopes to FLOW_END scopes. Similar
+// to ASYNC, a FLOW can consist of multiple phases. The first phase is defined
+// by the FLOW_BEGIN calls. Additional phases can be defined using the FLOW_STEP
+// macros. When the operation completes, call FLOW_END. An async operation can
+// span threads and processes, but all events in that operation must use the
+// same `name` and `id`. Each event can have its own args.
+#  define TRACE_EVENT_FLOW_BEGIN0(category, name, id)                        \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE)
+#  define TRACE_EVENT_FLOW_BEGIN1(category, name, id, arg1_name, arg1_val)   \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE,        \
+                                     arg1_name, arg1_val)
+#  define TRACE_EVENT_FLOW_BEGIN2(category, name, id, arg1_name, arg1_val,   \
+                                  arg2_name, arg2_val)                       \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE,        \
+                                     arg1_name, arg1_val, arg2_name, arg2_val)
+#  define TRACE_EVENT_COPY_FLOW_BEGIN0(category, name, id)                   \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_COPY)
+#  define TRACE_EVENT_COPY_FLOW_BEGIN1(category, name, id, arg1_name,        \
+                                       arg1_val)                             \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_COPY,        \
+                                     arg1_name, arg1_val)
+#  define TRACE_EVENT_COPY_FLOW_BEGIN2(category, name, id, arg1_name,        \
+                                       arg1_val, arg2_name, arg2_val)        \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_BEGIN, category, \
+                                     name, id, TRACE_EVENT_FLAG_COPY,        \
+                                     arg1_name, arg1_val, arg2_name, arg2_val)
+
+// Records a single FLOW_STEP event for `step` immediately. If the category
+// is not enabled, then this does nothing. The `name` and `id` must match the
+// FLOW_BEGIN event above. The `step` param identifies this step within the
+// async event. This should be called at the beginning of the next phase of an
+// asynchronous operation.
+#  define TRACE_EVENT_FLOW_STEP0(category, name, id, step)                    \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_STEP, category,   \
+                                     name, id, TRACE_EVENT_FLAG_NONE, "step", \
+                                     step)
+#  define TRACE_EVENT_FLOW_STEP1(category, name, id, step, arg1_name,         \
+                                 arg1_val)                                    \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_STEP, category,   \
+                                     name, id, TRACE_EVENT_FLAG_NONE, "step", \
+                                     step, arg1_name, arg1_val)
+#  define TRACE_EVENT_COPY_FLOW_STEP0(category, name, id, step)               \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_STEP, category,   \
+                                     name, id, TRACE_EVENT_FLAG_COPY, "step", \
+                                     step)
+#  define TRACE_EVENT_COPY_FLOW_STEP1(category, name, id, step, arg1_name,    \
+                                      arg1_val)                               \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_STEP, category,   \
+                                     name, id, TRACE_EVENT_FLAG_COPY, "step", \
+                                     step, arg1_name, arg1_val)
+
+// Records a single FLOW_END event for "name" immediately. If the category
+// is not enabled, then this does nothing.
+#  define TRACE_EVENT_FLOW_END0(category, name, id)                        \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE)
+#  define TRACE_EVENT_FLOW_END1(category, name, id, arg1_name, arg1_val)   \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE,      \
+                                     arg1_name, arg1_val)
+#  define TRACE_EVENT_FLOW_END2(category, name, id, arg1_name, arg1_val,   \
+                                arg2_name, arg2_val)                       \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category, \
+                                     name, id, TRACE_EVENT_FLAG_NONE,      \
+                                     arg1_name, arg1_val, arg2_name, arg2_val)
+#  define TRACE_EVENT_COPY_FLOW_END0(category, name, id)                   \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category, \
+                                     name, id, TRACE_EVENT_FLAG_COPY)
+#  define TRACE_EVENT_COPY_FLOW_END1(category, name, id, arg1_name, arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category,    \
+                                     name, id, TRACE_EVENT_FLAG_COPY,         \
+                                     arg1_name, arg1_val)
+#  define TRACE_EVENT_COPY_FLOW_END2(category, name, id, arg1_name, arg1_val, \
+                                     arg2_name, arg2_val)                     \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category,    \
+                                     name, id, TRACE_EVENT_FLAG_COPY,         \
+                                     arg1_name, arg1_val, arg2_name, arg2_val)
+
+////////////////////////////////////////////////////////////////////////////////
+// Implementation specific tracing API definitions.
+
+// Get a pointer to the enabled state of the given trace category. Only
+// long-lived literal strings should be given as the category name. The returned
+// pointer can be held permanently in a local static for example. If the
+// unsigned char is non-zero, tracing is enabled. If tracing is enabled,
+// TRACE_EVENT_API_ADD_TRACE_EVENT can be called. It's OK if tracing is disabled
+// between the load of the tracing state and the call to
+// TRACE_EVENT_API_ADD_TRACE_EVENT, because this flag only provides an early out
+// for best performance when tracing is disabled.
+// const unsigned char*
+//     TRACE_EVENT_API_GET_CATEGORY_ENABLED(const char* category_name)
+#  define TRACE_EVENT_API_GET_CATEGORY_ENABLED \
+    webrtc::EventTracer::GetCategoryEnabled
+
+// Add a trace event to the platform tracing system.
+// void TRACE_EVENT_API_ADD_TRACE_EVENT(
+//                    char phase,
+//                    const unsigned char* category_enabled,
+//                    const char* name,
+//                    unsigned long long id,
+//                    int num_args,
+//                    const char** arg_names,
+//                    const unsigned char* arg_types,
+//                    const unsigned long long* arg_values,
+//                    unsigned char flags)
+#  define TRACE_EVENT_API_ADD_TRACE_EVENT MOZ_INTERNAL_UPROFILER_SIMPLE_EVENT
+
+////////////////////////////////////////////////////////////////////////////////
+
+// Implementation detail: trace event macros create temporary variables
+// to keep instrumentation overhead low. These macros give each temporary
+// variable a unique name based on the line number to prevent name collissions.
+#  define INTERNAL_TRACE_EVENT_UID3(a, b) trace_event_unique_##a##b
+#  define INTERNAL_TRACE_EVENT_UID2(a, b) INTERNAL_TRACE_EVENT_UID3(a, b)
+#  define INTERNAL_TRACE_EVENT_UID(name_prefix) \
+    INTERNAL_TRACE_EVENT_UID2(name_prefix, __LINE__)
+
+#  if WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS
+#    define INTERNAL_TRACE_EVENT_INFO_TYPE const unsigned char*
+#  else
+#    define INTERNAL_TRACE_EVENT_INFO_TYPE static const unsigned char*
+#  endif  // WEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS
+
+// Implementation detail: internal macro to create static category.
+#  define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category)               \
+    INTERNAL_TRACE_EVENT_INFO_TYPE INTERNAL_TRACE_EVENT_UID(catstatic) = \
+        reinterpret_cast<const unsigned char*>(category);
+
+// Implementation detail: internal macro to create static category and add
+// event if the category is enabled.
+#  define INTERNAL_TRACE_EVENT_ADD(phase, category, name, flags, ...)        \
+    do {                                                                     \
+      INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category);                      \
+      if (*INTERNAL_TRACE_EVENT_UID(catstatic)) {                            \
+        webrtc::trace_event_internal::AddTraceEvent(                         \
+            phase, INTERNAL_TRACE_EVENT_UID(catstatic), name,                \
+            webrtc::trace_event_internal::kNoEventId, flags, ##__VA_ARGS__); \
+      }                                                                      \
+    } while (0)
+
+// Implementation detail: internal macro to create static category and add begin
+// event if the category is enabled. Also adds the end event when the scope
+// ends.
+#  define INTERNAL_TRACE_EVENT_ADD_SCOPED(category, name, ...)                \
+    INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category);                         \
+    webrtc::trace_event_internal::TraceEndOnScopeClose                        \
+        INTERNAL_TRACE_EVENT_UID(profileScope);                               \
+    if (*INTERNAL_TRACE_EVENT_UID(catstatic)) {                               \
+      webrtc::trace_event_internal::AddTraceEvent(                            \
+          TRACE_EVENT_PHASE_BEGIN, INTERNAL_TRACE_EVENT_UID(catstatic), name, \
+          webrtc::trace_event_internal::kNoEventId, TRACE_EVENT_FLAG_NONE,    \
+          ##__VA_ARGS__);                                                     \
+      INTERNAL_TRACE_EVENT_UID(profileScope)                                  \
+          .Initialize(INTERNAL_TRACE_EVENT_UID(catstatic), name);             \
+    }
+
+// Implementation detail: internal macro to create static category and add
+// event if the category is enabled.
+#  define INTERNAL_TRACE_EVENT_ADD_WITH_ID(phase, category, name, id, flags, \
+                                           ...)                              \
+    do {                                                                     \
+      INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category);                      \
+      if (*INTERNAL_TRACE_EVENT_UID(catstatic)) {                            \
+        unsigned char trace_event_flags = flags | TRACE_EVENT_FLAG_HAS_ID;   \
+        webrtc::trace_event_internal::TraceID trace_event_trace_id(          \
+            id, &trace_event_flags);                                         \
+        webrtc::trace_event_internal::AddTraceEvent(                         \
+            phase, INTERNAL_TRACE_EVENT_UID(catstatic), name,                \
+            trace_event_trace_id.data(), trace_event_flags, ##__VA_ARGS__);  \
+      }                                                                      \
+    } while (0)
+
+#  ifdef MOZ_GECKO_PROFILER
+#    define MOZ_INTERNAL_UPROFILER_SIMPLE_EVENT(phase, category_enabled, name, \
+                                                id, num_args, arg_names,       \
+                                                arg_types, arg_values, flags)  \
+      uprofiler_simple_event_marker(name, phase, num_args, arg_names,          \
+                                    arg_types, arg_values);
+#  else
+#    define MOZ_INTERNAL_UPROFILER_SIMPLE_EVENT(phase, category_enabled, name, \
+                                                id, num_args, arg_names,       \
+                                                arg_types, arg_values, flags)
+#  endif
+
+// Notes regarding the following definitions:
+// New values can be added and propagated to third party libraries, but existing
+// definitions must never be changed, because third party libraries may use old
+// definitions.
+
+// Phase indicates the nature of an event entry. E.g. part of a begin/end pair.
+#  define TRACE_EVENT_PHASE_BEGIN ('B')
+#  define TRACE_EVENT_PHASE_END ('E')
+#  define TRACE_EVENT_PHASE_INSTANT ('I')
+#  define TRACE_EVENT_PHASE_ASYNC_BEGIN ('S')
+#  define TRACE_EVENT_PHASE_ASYNC_STEP ('T')
+#  define TRACE_EVENT_PHASE_ASYNC_END ('F')
+#  define TRACE_EVENT_PHASE_FLOW_BEGIN ('s')
+#  define TRACE_EVENT_PHASE_FLOW_STEP ('t')
+#  define TRACE_EVENT_PHASE_FLOW_END ('f')
+#  define TRACE_EVENT_PHASE_METADATA ('M')
+#  define TRACE_EVENT_PHASE_COUNTER ('C')
+
+// Flags for changing the behavior of TRACE_EVENT_API_ADD_TRACE_EVENT.
+#  define TRACE_EVENT_FLAG_NONE (static_cast<unsigned char>(0))
+#  define TRACE_EVENT_FLAG_COPY (static_cast<unsigned char>(1 << 0))
+#  define TRACE_EVENT_FLAG_HAS_ID (static_cast<unsigned char>(1 << 1))
+#  define TRACE_EVENT_FLAG_MANGLE_ID (static_cast<unsigned char>(1 << 2))
+
+namespace webrtc {
+namespace trace_event_internal {
+
+// Specify these values when the corresponding argument of AddTraceEvent is not
+// used.
+const int kZeroNumArgs = 0;
+const unsigned long long kNoEventId = 0;
+
+// TraceID encapsulates an ID that can either be an integer or pointer. Pointers
+// are mangled with the Process ID so that they are unlikely to collide when the
+// same pointer is used on different processes.
+class TraceID {
+ public:
+  class ForceMangle {
+   public:
+    explicit ForceMangle(unsigned long long id) : data_(id) {}
+    explicit ForceMangle(unsigned long id) : data_(id) {}
+    explicit ForceMangle(unsigned int id) : data_(id) {}
+    explicit ForceMangle(unsigned short id) : data_(id) {}
+    explicit ForceMangle(unsigned char id) : data_(id) {}
+    explicit ForceMangle(long long id)
+        : data_(static_cast<unsigned long long>(id)) {}
+    explicit ForceMangle(long id)
+        : data_(static_cast<unsigned long long>(id)) {}
+    explicit ForceMangle(int id) : data_(static_cast<unsigned long long>(id)) {}
+    explicit ForceMangle(short id)
+        : data_(static_cast<unsigned long long>(id)) {}
+    explicit ForceMangle(signed char id)
+        : data_(static_cast<unsigned long long>(id)) {}
+
+    unsigned long long data() const { return data_; }
+
+   private:
+    unsigned long long data_;
+  };
+
+  explicit TraceID(const void* id, unsigned char* flags)
+      : data_(
+            static_cast<unsigned long long>(reinterpret_cast<uintptr_t>(id))) {
+    *flags |= TRACE_EVENT_FLAG_MANGLE_ID;
+  }
+  explicit TraceID(ForceMangle id, unsigned char* flags) : data_(id.data()) {
+    *flags |= TRACE_EVENT_FLAG_MANGLE_ID;
+  }
+  explicit TraceID(unsigned long long id, unsigned char* flags) : data_(id) {
+    (void)flags;
+  }
+  explicit TraceID(unsigned long id, unsigned char* flags) : data_(id) {
+    (void)flags;
+  }
+  explicit TraceID(unsigned int id, unsigned char* flags) : data_(id) {
+    (void)flags;
+  }
+  explicit TraceID(unsigned short id, unsigned char* flags) : data_(id) {
+    (void)flags;
+  }
+  explicit TraceID(unsigned char id, unsigned char* flags) : data_(id) {
+    (void)flags;
+  }
+  explicit TraceID(long long id, unsigned char* flags)
+      : data_(static_cast<unsigned long long>(id)) {
+    (void)flags;
+  }
+  explicit TraceID(long id, unsigned char* flags)
+      : data_(static_cast<unsigned long long>(id)) {
+    (void)flags;
+  }
+  explicit TraceID(int id, unsigned char* flags)
+      : data_(static_cast<unsigned long long>(id)) {
+    (void)flags;
+  }
+  explicit TraceID(short id, unsigned char* flags)
+      : data_(static_cast<unsigned long long>(id)) {
+    (void)flags;
+  }
+  explicit TraceID(signed char id, unsigned char* flags)
+      : data_(static_cast<unsigned long long>(id)) {
+    (void)flags;
+  }
+
+  unsigned long long data() const { return data_; }
+
+ private:
+  unsigned long long data_;
+};
+
+// Simple union to store various types as unsigned long long.
+union TraceValueUnion {
+  bool as_bool;
+  unsigned long long as_uint;
+  long long as_int;
+  double as_double;
+  const void* as_pointer;
+  const char* as_string;
+};
+
+// Simple container for const char* that should be copied instead of retained.
+class TraceStringWithCopy {
+ public:
+  explicit TraceStringWithCopy(const char* str) : str_(str) {}
+  operator const char*() const { return str_; }
+
+ private:
+  const char* str_;
+};
+
+// Define SetTraceValue for each allowed type. It stores the type and
+// value in the return arguments. This allows this API to avoid declaring any
+// structures so that it is portable to third_party libraries.
+#  define INTERNAL_DECLARE_SET_TRACE_VALUE(actual_type, union_member,      \
+                                           value_type_id)                  \
+    static inline void SetTraceValue(actual_type arg, unsigned char* type, \
+                                     unsigned long long* value) {          \
+      TraceValueUnion type_value;                                          \
+      type_value.union_member = arg;                                       \
+      *type = value_type_id;                                               \
+      *value = type_value.as_uint;                                         \
+    }
+// Simpler form for int types that can be safely casted.
+#  define INTERNAL_DECLARE_SET_TRACE_VALUE_INT(actual_type, value_type_id) \
+    static inline void SetTraceValue(actual_type arg, unsigned char* type, \
+                                     unsigned long long* value) {          \
+      *type = value_type_id;                                               \
+      *value = static_cast<unsigned long long>(arg);                       \
+    }
+
+INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned long long, TRACE_VALUE_TYPE_UINT)
+INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned long, TRACE_VALUE_TYPE_UINT)
+INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned int, TRACE_VALUE_TYPE_UINT)
+INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned short, TRACE_VALUE_TYPE_UINT)
+INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned char, TRACE_VALUE_TYPE_UINT)
+INTERNAL_DECLARE_SET_TRACE_VALUE_INT(long long, TRACE_VALUE_TYPE_INT)
+INTERNAL_DECLARE_SET_TRACE_VALUE_INT(long, TRACE_VALUE_TYPE_INT)
+INTERNAL_DECLARE_SET_TRACE_VALUE_INT(int, TRACE_VALUE_TYPE_INT)
+INTERNAL_DECLARE_SET_TRACE_VALUE_INT(short, TRACE_VALUE_TYPE_INT)
+INTERNAL_DECLARE_SET_TRACE_VALUE_INT(signed char, TRACE_VALUE_TYPE_INT)
+INTERNAL_DECLARE_SET_TRACE_VALUE(bool, as_bool, TRACE_VALUE_TYPE_BOOL)
+INTERNAL_DECLARE_SET_TRACE_VALUE(double, as_double, TRACE_VALUE_TYPE_DOUBLE)
+INTERNAL_DECLARE_SET_TRACE_VALUE(const void*, as_pointer,
+                                 TRACE_VALUE_TYPE_POINTER)
+INTERNAL_DECLARE_SET_TRACE_VALUE(const char*, as_string,
+                                 TRACE_VALUE_TYPE_STRING)
+INTERNAL_DECLARE_SET_TRACE_VALUE(const TraceStringWithCopy&, as_string,
+                                 TRACE_VALUE_TYPE_COPY_STRING)
+
+#  undef INTERNAL_DECLARE_SET_TRACE_VALUE
+#  undef INTERNAL_DECLARE_SET_TRACE_VALUE_INT
+
+// std::string version of SetTraceValue so that trace arguments can be strings.
+static inline void SetTraceValue(const std::string& arg, unsigned char* type,
+                                 unsigned long long* value) {
+  TraceValueUnion type_value;
+  type_value.as_string = arg.c_str();
+  *type = TRACE_VALUE_TYPE_COPY_STRING;
+  *value = type_value.as_uint;
+}
+
+// These AddTraceEvent template functions are defined here instead of in the
+// macro, because the arg_values could be temporary objects, such as
+// std::string. In order to store pointers to the internal c_str and pass
+// through to the tracing API, the arg_values must live throughout
+// these procedures.
+
+static inline void AddTraceEvent(char phase,
+                                 const unsigned char* category_enabled,
+                                 const char* name, unsigned long long id,
+                                 unsigned char flags) {
+  TRACE_EVENT_API_ADD_TRACE_EVENT(phase, category_enabled, name, id,
+                                  kZeroNumArgs, nullptr, nullptr, nullptr,
+                                  flags);
+}
+
+template <class ARG1_TYPE>
+static inline void AddTraceEvent(char phase,
+                                 const unsigned char* category_enabled,
+                                 const char* name, unsigned long long id,
+                                 unsigned char flags, const char* arg1_name,
+                                 const ARG1_TYPE& arg1_val) {
+  const int num_args = 1;
+  unsigned char arg_types[1];
+  unsigned long long arg_values[1];
+  SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
+  TRACE_EVENT_API_ADD_TRACE_EVENT(phase, category_enabled, name, id, num_args,
+                                  &arg1_name, arg_types, arg_values, flags);
+}
+
+template <class ARG1_TYPE, class ARG2_TYPE>
+static inline void AddTraceEvent(char phase,
+                                 const unsigned char* category_enabled,
+                                 const char* name, unsigned long long id,
+                                 unsigned char flags, const char* arg1_name,
+                                 const ARG1_TYPE& arg1_val,
+                                 const char* arg2_name,
+                                 const ARG2_TYPE& arg2_val) {
+  const int num_args = 2;
+  const char* arg_names[2] = {arg1_name, arg2_name};
+  unsigned char arg_types[2];
+  unsigned long long arg_values[2];
+  SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
+  SetTraceValue(arg2_val, &arg_types[1], &arg_values[1]);
+  TRACE_EVENT_API_ADD_TRACE_EVENT(phase, category_enabled, name, id, num_args,
+                                  arg_names, arg_types, arg_values, flags);
+}
+
+// Used by TRACE_EVENTx macro. Do not use directly.
+class TraceEndOnScopeClose {
+ public:
+  // Note: members of data_ intentionally left uninitialized. See Initialize.
+  TraceEndOnScopeClose() : p_data_(nullptr) {}
+  ~TraceEndOnScopeClose() {
+    if (p_data_) AddEventIfEnabled();
+  }
+
+  void Initialize(const unsigned char* category_enabled, const char* name) {
+    data_.category_enabled = category_enabled;
+    data_.name = name;
+    p_data_ = &data_;
+  }
+
+ private:
+  // Add the end event if the category is still enabled.
+  void AddEventIfEnabled() {
+    // Only called when p_data_ is non-null.
+    if (*p_data_->category_enabled) {
+      TRACE_EVENT_API_ADD_TRACE_EVENT(TRACE_EVENT_PHASE_END,
+                                      p_data_->category_enabled, p_data_->name,
+                                      kNoEventId, kZeroNumArgs, nullptr,
+                                      nullptr, nullptr, TRACE_EVENT_FLAG_NONE);
+    }
+  }
+
+  // This Data struct workaround is to avoid initializing all the members
+  // in Data during construction of this object, since this object is always
+  // constructed, even when tracing is disabled. If the members of Data were
+  // members of this class instead, compiler warnings occur about potential
+  // uninitialized accesses.
+  struct Data {
+    const unsigned char* category_enabled;
+    const char* name;
+  };
+  Data* p_data_;
+  Data data_;
+};
+
+}  // namespace trace_event_internal
+}  // namespace webrtc
+#else
+
+////////////////////////////////////////////////////////////////////////////////
+// This section defines no-op alternatives to the tracing macros when
+// RTC_DISABLE_TRACE_EVENTS is defined.
+
+#  define RTC_NOOP() \
+    do {             \
+    } while (0)
+
+#  define TRACE_STR_COPY(str) RTC_NOOP()
+
+#  define TRACE_DISABLED_BY_DEFAULT(name) "disabled-by-default-" name
+
+#  define TRACE_ID_MANGLE(id) 0
+
+#  define TRACE_EVENT0(category, name) RTC_NOOP()
+#  define TRACE_EVENT1(category, name, arg1_name, arg1_val) RTC_NOOP()
+#  define TRACE_EVENT2(category, name, arg1_name, arg1_val, arg2_name, \
+                       arg2_val)                                       \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_INSTANT0(category, name) RTC_NOOP()
+#  define TRACE_EVENT_INSTANT1(category, name, arg1_name, arg1_val) RTC_NOOP()
+
+#  define TRACE_EVENT_INSTANT2(category, name, arg1_name, arg1_val, arg2_name, \
+                               arg2_val)                                       \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_COPY_INSTANT0(category, name) RTC_NOOP()
+#  define TRACE_EVENT_COPY_INSTANT1(category, name, arg1_name, arg1_val) \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_INSTANT2(category, name, arg1_name, arg1_val, \
+                                    arg2_name, arg2_val)                 \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_BEGIN0(category, name) RTC_NOOP()
+#  define TRACE_EVENT_BEGIN1(category, name, arg1_name, arg1_val) RTC_NOOP()
+#  define TRACE_EVENT_BEGIN2(category, name, arg1_name, arg1_val, arg2_name, \
+                             arg2_val)                                       \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_BEGIN0(category, name) RTC_NOOP()
+#  define TRACE_EVENT_COPY_BEGIN1(category, name, arg1_name, arg1_val) \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_BEGIN2(category, name, arg1_name, arg1_val, \
+                                  arg2_name, arg2_val)                 \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_END0(category, name) RTC_NOOP()
+#  define TRACE_EVENT_END1(category, name, arg1_name, arg1_val) RTC_NOOP()
+#  define TRACE_EVENT_END2(category, name, arg1_name, arg1_val, arg2_name, \
+                           arg2_val)                                       \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_END0(category, name) RTC_NOOP()
+#  define TRACE_EVENT_COPY_END1(category, name, arg1_name, arg1_val) RTC_NOOP()
+#  define TRACE_EVENT_COPY_END2(category, name, arg1_name, arg1_val, \
+                                arg2_name, arg2_val)                 \
+    RTC_NOOP()
+
+#  define TRACE_COUNTER1(category, name, value) RTC_NOOP()
+#  define TRACE_COPY_COUNTER1(category, name, value) RTC_NOOP()
+
+#  define TRACE_COUNTER2(category, name, value1_name, value1_val, value2_name, \
+                         value2_val)                                           \
+    RTC_NOOP()
+#  define TRACE_COPY_COUNTER2(category, name, value1_name, value1_val, \
+                              value2_name, value2_val)                 \
+    RTC_NOOP()
+
+#  define TRACE_COUNTER_ID1(category, name, id, value) RTC_NOOP()
+#  define TRACE_COPY_COUNTER_ID1(category, name, id, value) RTC_NOOP()
+
+#  define TRACE_COUNTER_ID2(category, name, id, value1_name, value1_val, \
+                            value2_name, value2_val)                     \
+    RTC_NOOP()
+#  define TRACE_COPY_COUNTER_ID2(category, name, id, value1_name, value1_val, \
+                                 value2_name, value2_val)                     \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_ASYNC_BEGIN0(category, name, id) RTC_NOOP()
+#  define TRACE_EVENT_ASYNC_BEGIN1(category, name, id, arg1_name, arg1_val) \
+    RTC_NOOP()
+#  define TRACE_EVENT_ASYNC_BEGIN2(category, name, id, arg1_name, arg1_val, \
+                                   arg2_name, arg2_val)                     \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_ASYNC_BEGIN0(category, name, id) RTC_NOOP()
+#  define TRACE_EVENT_COPY_ASYNC_BEGIN1(category, name, id, arg1_name, \
+                                        arg1_val)                      \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_ASYNC_BEGIN2(category, name, id, arg1_name, \
+                                        arg1_val, arg2_name, arg2_val) \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_ASYNC_STEP0(category, name, id, step) RTC_NOOP()
+#  define TRACE_EVENT_ASYNC_STEP1(category, name, id, step, arg1_name, \
+                                  arg1_val)                            \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_ASYNC_STEP0(category, name, id, step) RTC_NOOP()
+#  define TRACE_EVENT_COPY_ASYNC_STEP1(category, name, id, step, arg1_name, \
+                                       arg1_val)                            \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_ASYNC_END0(category, name, id) RTC_NOOP()
+#  define TRACE_EVENT_ASYNC_END1(category, name, id, arg1_name, arg1_val) \
+    RTC_NOOP()
+#  define TRACE_EVENT_ASYNC_END2(category, name, id, arg1_name, arg1_val, \
+                                 arg2_name, arg2_val)                     \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_ASYNC_END0(category, name, id) RTC_NOOP()
+#  define TRACE_EVENT_COPY_ASYNC_END1(category, name, id, arg1_name, arg1_val) \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_ASYNC_END2(category, name, id, arg1_name, arg1_val, \
+                                      arg2_name, arg2_val)                     \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_FLOW_BEGIN0(category, name, id) RTC_NOOP()
+#  define TRACE_EVENT_FLOW_BEGIN1(category, name, id, arg1_name, arg1_val) \
+    RTC_NOOP()
+#  define TRACE_EVENT_FLOW_BEGIN2(category, name, id, arg1_name, arg1_val, \
+                                  arg2_name, arg2_val)                     \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_FLOW_BEGIN0(category, name, id) RTC_NOOP()
+#  define TRACE_EVENT_COPY_FLOW_BEGIN1(category, name, id, arg1_name, \
+                                       arg1_val)                      \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_FLOW_BEGIN2(category, name, id, arg1_name, \
+                                       arg1_val, arg2_name, arg2_val) \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_FLOW_STEP0(category, name, id, step) RTC_NOOP()
+#  define TRACE_EVENT_FLOW_STEP1(category, name, id, step, arg1_name, \
+                                 arg1_val)                            \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_FLOW_STEP0(category, name, id, step) RTC_NOOP()
+#  define TRACE_EVENT_COPY_FLOW_STEP1(category, name, id, step, arg1_name, \
+                                      arg1_val)                            \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_FLOW_END0(category, name, id) RTC_NOOP()
+#  define TRACE_EVENT_FLOW_END1(category, name, id, arg1_name, arg1_val) \
+    RTC_NOOP()
+#  define TRACE_EVENT_FLOW_END2(category, name, id, arg1_name, arg1_val, \
+                                arg2_name, arg2_val)                     \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_FLOW_END0(category, name, id) RTC_NOOP()
+#  define TRACE_EVENT_COPY_FLOW_END1(category, name, id, arg1_name, arg1_val) \
+    RTC_NOOP()
+#  define TRACE_EVENT_COPY_FLOW_END2(category, name, id, arg1_name, arg1_val, \
+                                     arg2_name, arg2_val)                     \
+    RTC_NOOP()
+
+#  define TRACE_EVENT_API_GET_CATEGORY_ENABLED ""
+
+#  define TRACE_EVENT_API_ADD_TRACE_EVENT RTC_NOOP()
+
+#endif  // RTC_TRACE_EVENTS_ENABLED
+
+#endif  // GECKO_TRACE_EVENT_H_
diff --git a/tools/profiler/public/MicroGeckoProfiler.h b/tools/profiler/public/MicroGeckoProfiler.h
new file mode 100644
index 0000000000..7b735e1eec
--- /dev/null
+++ b/tools/profiler/public/MicroGeckoProfiler.h
@@ -0,0 +1,130 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This contains things related to the Gecko profiler, for use in third_party
+// code. It is very minimal and is designed to be used by patching over
+// upstream code.
+// Only use the C ABI and guard C++ code with #ifdefs, don't pull anything from
+// Gecko, it must be possible to include the header file into any C++ codebase.
+
+#ifndef MICRO_GECKO_PROFILER
+#define MICRO_GECKO_PROFILER
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <mozilla/Types.h>
+#include <stdio.h>
+
+#ifdef _WIN32
+#  include <libloaderapi.h>
+#else
+#  include <dlfcn.h>
+#endif
+
+extern MOZ_EXPORT void uprofiler_register_thread(const char* aName,
+                                                 void* aGuessStackTop);
+
+extern MOZ_EXPORT void uprofiler_unregister_thread();
+
+extern MOZ_EXPORT void uprofiler_simple_event_marker(
+    const char* name, char phase, int num_args, const char** arg_names,
+    const unsigned char* arg_types, const unsigned long long* arg_values);
+#ifdef __cplusplus
+}
+
+struct AutoRegisterProfiler {
+  AutoRegisterProfiler(const char* name, char* stacktop) {
+    if (getenv("MOZ_UPROFILER_LOG_THREAD_CREATION")) {
+      printf("### UProfiler: new thread: '%s'\n", name);
+    }
+    uprofiler_register_thread(name, stacktop);
+  }
+  ~AutoRegisterProfiler() { uprofiler_unregister_thread(); }
+};
+#endif  // __cplusplus
+
+void uprofiler_simple_event_marker(const char* name, char phase, int num_args,
+                                   const char** arg_names,
+                                   const unsigned char* arg_types,
+                                   const unsigned long long* arg_values);
+
+struct UprofilerFuncPtrs {
+  void (*register_thread)(const char* aName, void* aGuessStackTop);
+  void (*unregister_thread)();
+  void (*simple_event_marker)(const char* name, char phase, int num_args,
+                              const char** arg_names,
+                              const unsigned char* arg_types,
+                              const unsigned long long* arg_values);
+};
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-function"
+
+static void register_thread_noop(const char* aName, void* aGuessStackTop) {
+  /* no-op */
+}
+static void unregister_thread_noop() { /* no-op */
+}
+static void simple_event_marker_noop(const char* name, char phase, int num_args,
+                                     const char** arg_names,
+                                     const unsigned char* arg_types,
+                                     const unsigned long long* arg_values) {
+  /* no-op */
+}
+
+#pragma GCC diagnostic pop
+
+#if defined(_WIN32)
+#  define UPROFILER_OPENLIB() GetModuleHandle(NULL)
+#else
+#  define UPROFILER_OPENLIB() dlopen(NULL, RTLD_NOW)
+#endif
+
+#if defined(_WIN32)
+#  define UPROFILER_GET_SYM(handle, sym) GetProcAddress(handle, sym)
+#else
+#  define UPROFILER_GET_SYM(handle, sym) dlsym(handle, sym)
+#endif
+
+#if defined(_WIN32)
+#  define UPROFILER_PRINT_ERROR(func) fprintf(stderr, "%s error\n", #func);
+#else
+#  define UPROFILER_PRINT_ERROR(func) \
+    fprintf(stderr, "%s error: %s\n", #func, dlerror());
+#endif
+
+// Assumes that a variable of type UprofilerFuncPtrs, named uprofiler
+// is accessible in the scope
+#define UPROFILER_GET_FUNCTIONS()                                 \
+  void* handle = UPROFILER_OPENLIB();                             \
+  if (!handle) {                                                  \
+    UPROFILER_PRINT_ERROR(UPROFILER_OPENLIB);                     \
+    uprofiler.register_thread = register_thread_noop;             \
+    uprofiler.unregister_thread = unregister_thread_noop;         \
+    uprofiler.simple_event_marker = simple_event_marker_noop;     \
+  }                                                               \
+  uprofiler.register_thread =                                     \
+      UPROFILER_GET_SYM(handle, "uprofiler_register_thread");     \
+  if (!uprofiler.register_thread) {                               \
+    UPROFILER_PRINT_ERROR(uprofiler_unregister_thread);           \
+    uprofiler.register_thread = register_thread_noop;             \
+  }                                                               \
+  uprofiler.unregister_thread =                                   \
+      UPROFILER_GET_SYM(handle, "uprofiler_unregister_thread");   \
+  if (!uprofiler.unregister_thread) {                             \
+    UPROFILER_PRINT_ERROR(uprofiler_unregister_thread);           \
+    uprofiler.unregister_thread = unregister_thread_noop;         \
+  }                                                               \
+  uprofiler.simple_event_marker =                                 \
+      UPROFILER_GET_SYM(handle, "uprofiler_simple_event_marker"); \
+  if (!uprofiler.simple_event_marker) {                           \
+    UPROFILER_PRINT_ERROR(uprofiler_simple_event_marker);         \
+    uprofiler.simple_event_marker = simple_event_marker_noop;     \
+  }
+
+#endif  // MICRO_GECKO_PROFILER
diff --git a/tools/profiler/public/ProfileAdditionalInformation.h b/tools/profiler/public/ProfileAdditionalInformation.h
new file mode 100644
index 0000000000..c4cc8697b0
--- /dev/null
+++ b/tools/profiler/public/ProfileAdditionalInformation.h
@@ -0,0 +1,90 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// The Gecko Profiler is an always-on profiler that takes fast and low overhead
+// samples of the program execution using only userspace functionality for
+// portability. The goal of this module is to provide performance data in a
+// generic cross-platform way without requiring custom tools or kernel support.
+//
+// Samples are collected to form a timeline with optional timeline event
+// (markers) used for filtering. The samples include both native stacks and
+// platform-independent "label stack" frames.
+
+#ifndef ProfileAdditionalInformation_h
+#define ProfileAdditionalInformation_h
+
+#ifdef MOZ_GECKO_PROFILER
+#  include "shared-libraries.h"
+#endif
+#include "js/Value.h"
+#include "nsString.h"
+
+namespace IPC {
+class MessageReader;
+class MessageWriter;
+template <typename T>
+struct ParamTraits;
+}  // namespace IPC
+
+namespace mozilla {
+// This structure contains additional information gathered while generating the
+// profile json and iterating the buffer.
+struct ProfileGenerationAdditionalInformation {
+#ifdef MOZ_GECKO_PROFILER
+  ProfileGenerationAdditionalInformation() = default;
+  explicit ProfileGenerationAdditionalInformation(
+      const SharedLibraryInfo&& aSharedLibraries)
+      : mSharedLibraries(aSharedLibraries) {}
+
+  size_t SizeOf() const { return mSharedLibraries.SizeOf(); }
+
+  void Append(ProfileGenerationAdditionalInformation&& aOther) {
+    mSharedLibraries.AddAllSharedLibraries(aOther.mSharedLibraries);
+  }
+
+  void FinishGathering() { mSharedLibraries.DeduplicateEntries(); }
+
+  void ToJSValue(JSContext* aCx, JS::MutableHandle<JS::Value> aRetVal) const;
+
+  SharedLibraryInfo mSharedLibraries;
+#endif  // MOZ_GECKO_PROFILER
+};
+
+struct ProfileAndAdditionalInformation {
+  ProfileAndAdditionalInformation() = default;
+  explicit ProfileAndAdditionalInformation(const nsCString&& aProfile)
+      : mProfile(aProfile) {}
+
+  ProfileAndAdditionalInformation(
+      const nsCString&& aProfile,
+      const ProfileGenerationAdditionalInformation&& aAdditionalInformation)
+      : mProfile(aProfile),
+        mAdditionalInformation(Some(aAdditionalInformation)) {}
+
+  size_t SizeOf() const {
+    size_t size = mProfile.Length();
+#ifdef MOZ_GECKO_PROFILER
+    if (mAdditionalInformation.isSome()) {
+      size += mAdditionalInformation->SizeOf();
+    }
+#endif
+    return size;
+  }
+
+  nsCString mProfile;
+  Maybe<ProfileGenerationAdditionalInformation> mAdditionalInformation;
+};
+}  // namespace mozilla
+
+namespace IPC {
+template <>
+struct ParamTraits<mozilla::ProfileGenerationAdditionalInformation> {
+  typedef mozilla::ProfileGenerationAdditionalInformation paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam);
+  static bool Read(MessageReader* aReader, paramType* aResult);
+};
+}  // namespace IPC
+
+#endif  // ProfileAdditionalInformation_h
diff --git a/tools/profiler/public/ProfileBufferEntrySerializationGeckoExtensions.h b/tools/profiler/public/ProfileBufferEntrySerializationGeckoExtensions.h
new file mode 100644
index 0000000000..1578bd2ddc
--- /dev/null
+++ b/tools/profiler/public/ProfileBufferEntrySerializationGeckoExtensions.h
@@ -0,0 +1,160 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfileBufferEntrySerializationGeckoExtensions_h
+#define ProfileBufferEntrySerializationGeckoExtensions_h
+
+#include "mozilla/ProfileBufferEntrySerialization.h"
+
+#include "js/AllocPolicy.h"
+#include "js/Utility.h"
+#include "nsString.h"
+
+namespace mozilla {
+
+// ----------------------------------------------------------------------------
+// ns[C]String
+
+// nsString or nsCString contents are serialized as the number of bytes (encoded
+// as ULEB128) and all the characters in the string. The terminal '\0' is
+// omitted.
+// Make sure you write and read with the same character type!
+//
+// Usage: `nsCString s = ...; aEW.WriteObject(s);`
+template <typename CHAR>
+struct ProfileBufferEntryWriter::Serializer<nsTString<CHAR>> {
+  static Length Bytes(const nsTString<CHAR>& aS) {
+    const auto length = aS.Length();
+    return ProfileBufferEntryWriter::ULEB128Size(length) +
+           static_cast<Length>(length * sizeof(CHAR));
+  }
+
+  static void Write(ProfileBufferEntryWriter& aEW, const nsTString<CHAR>& aS) {
+    const auto length = aS.Length();
+    aEW.WriteULEB128(length);
+    // Copy the bytes from the string's buffer.
+    aEW.WriteBytes(aS.Data(), length * sizeof(CHAR));
+  }
+};
+
+template <typename CHAR>
+struct ProfileBufferEntryReader::Deserializer<nsTString<CHAR>> {
+  static void ReadInto(ProfileBufferEntryReader& aER, nsTString<CHAR>& aS) {
+    aS = Read(aER);
+  }
+
+  static nsTString<CHAR> Read(ProfileBufferEntryReader& aER) {
+    const Length length = aER.ReadULEB128<Length>();
+    nsTString<CHAR> s;
+    // BulkWrite is the most efficient way to copy bytes into the target string.
+    auto writerOrErr = s.BulkWrite(length, 0, true);
+    MOZ_RELEASE_ASSERT(!writerOrErr.isErr());
+
+    auto writer = writerOrErr.unwrap();
+
+    aER.ReadBytes(writer.Elements(), length * sizeof(CHAR));
+    writer.Finish(length, true);
+    return s;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// nsAuto[C]String
+
+// nsAuto[C]String contents are serialized as the number of bytes (encoded as
+// ULEB128) and all the characters in the string. The terminal '\0' is omitted.
+// Make sure you write and read with the same character type!
+//
+// Usage: `nsAutoCString s = ...; aEW.WriteObject(s);`
+template <typename CHAR, size_t N>
+struct ProfileBufferEntryWriter::Serializer<nsTAutoStringN<CHAR, N>> {
+  static Length Bytes(const nsTAutoStringN<CHAR, N>& aS) {
+    const auto length = aS.Length();
+    return ProfileBufferEntryWriter::ULEB128Size(length) +
+           static_cast<Length>(length * sizeof(CHAR));
+  }
+
+  static void Write(ProfileBufferEntryWriter& aEW,
+                    const nsTAutoStringN<CHAR, N>& aS) {
+    const auto length = aS.Length();
+    aEW.WriteULEB128(length);
+    // Copy the bytes from the string's buffer.
+    aEW.WriteBytes(aS.BeginReading(), length * sizeof(CHAR));
+  }
+};
+
+template <typename CHAR, size_t N>
+struct ProfileBufferEntryReader::Deserializer<nsTAutoStringN<CHAR, N>> {
+  static void ReadInto(ProfileBufferEntryReader& aER,
+                       nsTAutoStringN<CHAR, N>& aS) {
+    aS = Read(aER);
+  }
+
+  static nsTAutoStringN<CHAR, N> Read(ProfileBufferEntryReader& aER) {
+    const auto length = aER.ReadULEB128<Length>();
+    nsTAutoStringN<CHAR, N> s;
+    // BulkWrite is the most efficient way to copy bytes into the target string.
+    auto writerOrErr = s.BulkWrite(length, 0, true);
+    MOZ_RELEASE_ASSERT(!writerOrErr.isErr());
+
+    auto writer = writerOrErr.unwrap();
+    aER.ReadBytes(writer.Elements(), length * sizeof(CHAR));
+    writer.Finish(length, true);
+    return s;
+  }
+};
+
+// ----------------------------------------------------------------------------
+// JS::UniqueChars
+
+// JS::UniqueChars contents are serialized as the number of bytes (encoded as
+// ULEB128) and all the characters in the string. The terminal '\0' is omitted.
+// Note: A nullptr pointer will be serialized like an empty string, so when
+// deserializing it will result in an allocated buffer only containing a
+// single null terminator.
+//
+// Usage: `JS::UniqueChars s = ...; aEW.WriteObject(s);`
+template <>
+struct ProfileBufferEntryWriter::Serializer<JS::UniqueChars> {
+  static Length Bytes(const JS::UniqueChars& aS) {
+    if (!aS) {
+      return ProfileBufferEntryWriter::ULEB128Size<Length>(0);
+    }
+    const auto len = static_cast<Length>(strlen(aS.get()));
+    return ProfileBufferEntryWriter::ULEB128Size(len) + len;
+  }
+
+  static void Write(ProfileBufferEntryWriter& aEW, const JS::UniqueChars& aS) {
+    if (!aS) {
+      aEW.WriteULEB128<Length>(0);
+      return;
+    }
+    const auto len = static_cast<Length>(strlen(aS.get()));
+    aEW.WriteULEB128(len);
+    aEW.WriteBytes(aS.get(), len);
+  }
+};
+
+template <>
+struct ProfileBufferEntryReader::Deserializer<JS::UniqueChars> {
+  static void ReadInto(ProfileBufferEntryReader& aER, JS::UniqueChars& aS) {
+    aS = Read(aER);
+  }
+
+  static JS::UniqueChars Read(ProfileBufferEntryReader& aER) {
+    const auto len = aER.ReadULEB128<Length>();
+    // Use the same allocation policy as JS_smprintf.
+    char* buffer =
+        static_cast<char*>(js::SystemAllocPolicy{}.pod_malloc<char>(len + 1));
+    aER.ReadBytes(buffer, len);
+    buffer[len] = '\0';
+    return JS::UniqueChars(buffer);
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // ProfileBufferEntrySerializationGeckoExtensions_h
diff --git a/tools/profiler/public/ProfileJSONWriter.h b/tools/profiler/public/ProfileJSONWriter.h
new file mode 100644
index 0000000000..8d23d7a890
--- /dev/null
+++ b/tools/profiler/public/ProfileJSONWriter.h
@@ -0,0 +1,19 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef PROFILEJSONWRITER_H
+#define PROFILEJSONWRITER_H
+
+#include "mozilla/BaseProfileJSONWriter.h"
+
+using ChunkedJSONWriteFunc = mozilla::baseprofiler::ChunkedJSONWriteFunc;
+using JSONSchemaWriter = mozilla::baseprofiler::JSONSchemaWriter;
+using OStreamJSONWriteFunc = mozilla::baseprofiler::OStreamJSONWriteFunc;
+using SpliceableChunkedJSONWriter =
+    mozilla::baseprofiler::SpliceableChunkedJSONWriter;
+using SpliceableJSONWriter = mozilla::baseprofiler::SpliceableJSONWriter;
+using UniqueJSONStrings = mozilla::baseprofiler::UniqueJSONStrings;
+
+#endif  // PROFILEJSONWRITER_H
diff --git a/tools/profiler/public/ProfilerBindings.h b/tools/profiler/public/ProfilerBindings.h
new file mode 100644
index 0000000000..096a860130
--- /dev/null
+++ b/tools/profiler/public/ProfilerBindings.h
@@ -0,0 +1,162 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* FFI functions for Profiler Rust API to call into profiler */
+
+#ifndef ProfilerBindings_h
+#define ProfilerBindings_h
+
+#include "mozilla/BaseProfilerMarkersPrerequisites.h"
+
+#include <cstddef>
+#include <stdint.h>
+
+namespace mozilla {
+class AutoProfilerLabel;
+class MarkerSchema;
+class MarkerTiming;
+class TimeStamp;
+enum class StackCaptureOptions;
+
+namespace baseprofiler {
+enum class ProfilingCategoryPair : uint32_t;
+class SpliceableJSONWriter;
+}  // namespace baseprofiler
+
+}  // namespace mozilla
+
+namespace JS {
+enum class ProfilingCategoryPair : uint32_t;
+}  // namespace JS
+
+// Everything in here is safe to include unconditionally, implementations must
+// take !MOZ_GECKO_PROFILER into account.
+extern "C" {
+
+void gecko_profiler_register_thread(const char* aName);
+void gecko_profiler_unregister_thread();
+
+void gecko_profiler_construct_label(mozilla::AutoProfilerLabel* aAutoLabel,
+                                    JS::ProfilingCategoryPair aCategoryPair);
+void gecko_profiler_destruct_label(mozilla::AutoProfilerLabel* aAutoLabel);
+
+// Construct, clone and destruct the timestamp for profiler time.
+void gecko_profiler_construct_timestamp_now(mozilla::TimeStamp* aTimeStamp);
+void gecko_profiler_clone_timestamp(const mozilla::TimeStamp* aSrcTimeStamp,
+                                    mozilla::TimeStamp* aDestTimeStamp);
+void gecko_profiler_destruct_timestamp(mozilla::TimeStamp* aTimeStamp);
+
+// Addition and subtraction for timestamp.
+void gecko_profiler_add_timestamp(const mozilla::TimeStamp* aTimeStamp,
+                                  mozilla::TimeStamp* aDestTimeStamp,
+                                  double aMicroseconds);
+void gecko_profiler_subtract_timestamp(const mozilla::TimeStamp* aTimeStamp,
+                                       mozilla::TimeStamp* aDestTimeStamp,
+                                       double aMicroseconds);
+
+// Various MarkerTiming constructors and a destructor.
+void gecko_profiler_construct_marker_timing_instant_at(
+    mozilla::MarkerTiming* aMarkerTiming, const mozilla::TimeStamp* aTime);
+void gecko_profiler_construct_marker_timing_instant_now(
+    mozilla::MarkerTiming* aMarkerTiming);
+void gecko_profiler_construct_marker_timing_interval(
+    mozilla::MarkerTiming* aMarkerTiming, const mozilla::TimeStamp* aStartTime,
+    const mozilla::TimeStamp* aEndTime);
+void gecko_profiler_construct_marker_timing_interval_until_now_from(
+    mozilla::MarkerTiming* aMarkerTiming, const mozilla::TimeStamp* aStartTime);
+void gecko_profiler_construct_marker_timing_interval_start(
+    mozilla::MarkerTiming* aMarkerTiming, const mozilla::TimeStamp* aTime);
+void gecko_profiler_construct_marker_timing_interval_end(
+    mozilla::MarkerTiming* aMarkerTiming, const mozilla::TimeStamp* aTime);
+void gecko_profiler_destruct_marker_timing(
+    mozilla::MarkerTiming* aMarkerTiming);
+
+// MarkerSchema constructors and destructor.
+void gecko_profiler_construct_marker_schema(
+    mozilla::MarkerSchema* aMarkerSchema,
+    const mozilla::MarkerSchema::Location* aLocations, size_t aLength);
+void gecko_profiler_construct_marker_schema_with_special_front_end_location(
+    mozilla::MarkerSchema* aMarkerSchema);
+void gecko_profiler_destruct_marker_schema(
+    mozilla::MarkerSchema* aMarkerSchema);
+
+// MarkerSchema methods for adding labels.
+void gecko_profiler_marker_schema_set_chart_label(
+    mozilla::MarkerSchema* aSchema, const char* aLabel, size_t aLabelLength);
+void gecko_profiler_marker_schema_set_tooltip_label(
+    mozilla::MarkerSchema* aSchema, const char* aLabel, size_t aLabelLength);
+void gecko_profiler_marker_schema_set_table_label(
+    mozilla::MarkerSchema* aSchema, const char* aLabel, size_t aLabelLength);
+void gecko_profiler_marker_schema_set_all_labels(mozilla::MarkerSchema* aSchema,
+                                                 const char* aLabel,
+                                                 size_t aLabelLength);
+
+// MarkerSchema methods for adding key/key-label values.
+void gecko_profiler_marker_schema_add_key_format(
+    mozilla::MarkerSchema* aSchema, const char* aKey, size_t aKeyLength,
+    mozilla::MarkerSchema::Format aFormat);
+void gecko_profiler_marker_schema_add_key_label_format(
+    mozilla::MarkerSchema* aSchema, const char* aKey, size_t aKeyLength,
+    const char* aLabel, size_t aLabelLength,
+    mozilla::MarkerSchema::Format aFormat);
+void gecko_profiler_marker_schema_add_key_format_searchable(
+    mozilla::MarkerSchema* aSchema, const char* aKey, size_t aKeyLength,
+    mozilla::MarkerSchema::Format aFormat,
+    mozilla::MarkerSchema::Searchable aSearchable);
+void gecko_profiler_marker_schema_add_key_label_format_searchable(
+    mozilla::MarkerSchema* aSchema, const char* aKey, size_t aKeyLength,
+    const char* aLabel, size_t aLabelLength,
+    mozilla::MarkerSchema::Format aFormat,
+    mozilla::MarkerSchema::Searchable aSearchable);
+void gecko_profiler_marker_schema_add_static_label_value(
+    mozilla::MarkerSchema* aSchema, const char* aLabel, size_t aLabelLength,
+    const char* aValue, size_t aValueLength);
+
+// Stream MarkerSchema to SpliceableJSONWriter.
+void gecko_profiler_marker_schema_stream(
+    mozilla::baseprofiler::SpliceableJSONWriter* aWriter, const char* aName,
+    size_t aNameLength, mozilla::MarkerSchema* aMarkerSchema,
+    void* aStreamedNamesSet);
+
+// Various SpliceableJSONWriter methods to add properties.
+void gecko_profiler_json_writer_int_property(
+    mozilla::baseprofiler::SpliceableJSONWriter* aWriter, const char* aName,
+    size_t aNameLength, int64_t aValue);
+void gecko_profiler_json_writer_float_property(
+    mozilla::baseprofiler::SpliceableJSONWriter* aWriter, const char* aName,
+    size_t aNameLength, double aValue);
+void gecko_profiler_json_writer_bool_property(
+    mozilla::baseprofiler::SpliceableJSONWriter* aWriter, const char* aName,
+    size_t aNameLength, bool aValue);
+void gecko_profiler_json_writer_string_property(
+    mozilla::baseprofiler::SpliceableJSONWriter* aWriter, const char* aName,
+    size_t aNameLength, const char* aValue, size_t aValueLength);
+void gecko_profiler_json_writer_null_property(
+    mozilla::baseprofiler::SpliceableJSONWriter* aWriter, const char* aName,
+    size_t aNameLength);
+
+// Marker APIs.
+void gecko_profiler_add_marker_untyped(
+    const char* aName, size_t aNameLength,
+    mozilla::baseprofiler::ProfilingCategoryPair aCategoryPair,
+    mozilla::MarkerTiming* aMarkerTiming,
+    mozilla::StackCaptureOptions aStackCaptureOptions);
+void gecko_profiler_add_marker_text(
+    const char* aName, size_t aNameLength,
+    mozilla::baseprofiler::ProfilingCategoryPair aCategoryPair,
+    mozilla::MarkerTiming* aMarkerTiming,
+    mozilla::StackCaptureOptions aStackCaptureOptions, const char* aText,
+    size_t aTextLength);
+void gecko_profiler_add_marker(
+    const char* aName, size_t aNameLength,
+    mozilla::baseprofiler::ProfilingCategoryPair aCategoryPair,
+    mozilla::MarkerTiming* aMarkerTiming,
+    mozilla::StackCaptureOptions aStackCaptureOptions, uint8_t aMarkerTag,
+    const uint8_t* aPayload, size_t aPayloadSize);
+
+}  // extern "C"
+
+#endif  // ProfilerBindings_h
diff --git a/tools/profiler/public/ProfilerChild.h b/tools/profiler/public/ProfilerChild.h
new file mode 100644
index 0000000000..a781784aae
--- /dev/null
+++ b/tools/profiler/public/ProfilerChild.h
@@ -0,0 +1,106 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerChild_h
+#define ProfilerChild_h
+
+#include "mozilla/BaseProfilerDetail.h"
+#include "mozilla/DataMutex.h"
+#include "mozilla/PProfilerChild.h"
+#include "mozilla/ProfileBufferControlledChunkManager.h"
+#include "mozilla/ProgressLogger.h"
+#include "mozilla/RefPtr.h"
+#include "ProfileAdditionalInformation.h"
+
+class nsIThread;
+struct PRThread;
+
+namespace mozilla {
+
+// The ProfilerChild actor is created in all processes except for the main
+// process. The corresponding ProfilerParent actor is created in the main
+// process, and it will notify us about profiler state changes and request
+// profiles from us.
+class ProfilerChild final : public PProfilerChild,
+                            public mozilla::ipc::IShmemAllocator {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ProfilerChild, final)
+
+  ProfilerChild();
+
+  // Collects and returns a profile.
+  // This method can be used to grab a profile just before PProfiler is torn
+  // down. The collected profile should then be sent through a different
+  // message channel that is guaranteed to stay open long enough.
+  ProfileAndAdditionalInformation GrabShutdownProfile();
+
+  void Destroy();
+
+  // This should be called regularly from outside of the profiler lock.
+  static void ProcessPendingUpdate();
+
+  static bool IsLockedOnCurrentThread();
+
+ private:
+  virtual ~ProfilerChild();
+
+  mozilla::ipc::IPCResult RecvStart(const ProfilerInitParams& params,
+                                    StartResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvEnsureStarted(
+      const ProfilerInitParams& params,
+      EnsureStartedResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvStop(StopResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvPause(PauseResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvResume(ResumeResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvPauseSampling(
+      PauseSamplingResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvResumeSampling(
+      ResumeSamplingResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvWaitOnePeriodicSampling(
+      WaitOnePeriodicSamplingResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvAwaitNextChunkManagerUpdate(
+      AwaitNextChunkManagerUpdateResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvDestroyReleasedChunksAtOrBefore(
+      const TimeStamp& aTimeStamp) override;
+  mozilla::ipc::IPCResult RecvGatherProfile(
+      GatherProfileResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvGetGatherProfileProgress(
+      GetGatherProfileProgressResolver&& aResolve) override;
+  mozilla::ipc::IPCResult RecvClearAllPages() override;
+
+  void ActorDestroy(ActorDestroyReason aActorDestroyReason) override;
+
+  FORWARD_SHMEM_ALLOCATOR_TO(PProfilerChild)
+
+  void SetupChunkManager();
+  void ResetChunkManager();
+  void ResolveChunkUpdate(
+      PProfilerChild::AwaitNextChunkManagerUpdateResolver& aResolve);
+  void ProcessChunkManagerUpdate(
+      ProfileBufferControlledChunkManager::Update&& aUpdate);
+
+  static void GatherProfileThreadFunction(void* already_AddRefedParameters);
+
+  nsCOMPtr<nsIThread> mThread;
+  bool mDestroyed;
+
+  ProfileBufferControlledChunkManager* mChunkManager = nullptr;
+  AwaitNextChunkManagerUpdateResolver mAwaitNextChunkManagerUpdateResolver;
+  ProfileBufferControlledChunkManager::Update mChunkManagerUpdate;
+
+  struct ProfilerChildAndUpdate {
+    RefPtr<ProfilerChild> mProfilerChild;
+    ProfileBufferControlledChunkManager::Update mUpdate;
+  };
+  static DataMutexBase<ProfilerChildAndUpdate,
+                       baseprofiler::detail::BaseProfilerMutex>
+      sPendingChunkManagerUpdate;
+
+  RefPtr<ProgressLogger::SharedProgress> mGatherProfileProgress;
+};
+
+}  // namespace mozilla
+
+#endif  // ProfilerChild_h
diff --git a/tools/profiler/public/ProfilerCodeAddressService.h b/tools/profiler/public/ProfilerCodeAddressService.h
new file mode 100644
index 0000000000..9d75c363b3
--- /dev/null
+++ b/tools/profiler/public/ProfilerCodeAddressService.h
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerCodeAddressService_h
+#define ProfilerCodeAddressService_h
+
+#include "CodeAddressService.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+
+// This SymbolTable struct, and the CompactSymbolTable struct in the
+// profiler rust module, have the exact same memory layout.
+// nsTArray and ThinVec are FFI-compatible, because the thin-vec crate is
+// being compiled with the "gecko-ffi" feature enabled.
+struct SymbolTable {
+  SymbolTable() = default;
+  SymbolTable(SymbolTable&& aOther) = default;
+
+  nsTArray<uint32_t> mAddrs;
+  nsTArray<uint32_t> mIndex;
+  nsTArray<uint8_t> mBuffer;
+};
+
+}  // namespace mozilla
+
+/**
+ * Cache and look up function symbol names.
+ *
+ * We don't template this on AllocPolicy since we need to use nsTArray in
+ * SymbolTable above, which doesn't work with AllocPolicy.  (We can't switch
+ * to Vector, as we would lose FFI compatibility with ThinVec.)
+ */
+class ProfilerCodeAddressService : public mozilla::CodeAddressService<> {
+ public:
+  // Like GetLocation, but only returns the symbol name.
+  bool GetFunction(const void* aPc, nsACString& aResult);
+
+ private:
+#if defined(XP_LINUX) || defined(XP_FREEBSD)
+  // Map of library names (owned by mLibraryStrings) to SymbolTables filled
+  // in by profiler_get_symbol_table.
+  mozilla::HashMap<const char*, mozilla::SymbolTable,
+                   mozilla::DefaultHasher<const char*>, AllocPolicy>
+      mSymbolTables;
+#endif
+};
+
+#endif  // ProfilerCodeAddressService_h
diff --git a/tools/profiler/public/ProfilerControl.h b/tools/profiler/public/ProfilerControl.h
new file mode 100644
index 0000000000..466d15eb69
--- /dev/null
+++ b/tools/profiler/public/ProfilerControl.h
@@ -0,0 +1,190 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// APIs that control the lifetime of the profiler: Initialization, start, pause,
+// resume, stop, and shutdown.
+
+#ifndef ProfilerControl_h
+#define ProfilerControl_h
+
+#include "mozilla/BaseProfilerRAIIMacro.h"
+
+// Everything in here is also safe to include unconditionally, and only defines
+// empty macros if MOZ_GECKO_PROFILER is unset.
+// If your file only uses particular APIs (e.g., only markers), please consider
+// including only the needed headers instead of this one, to reduce compilation
+// dependencies.
+
+enum class IsFastShutdown {
+  No,
+  Yes,
+};
+
+#ifndef MOZ_GECKO_PROFILER
+
+// This file can be #included unconditionally. However, everything within this
+// file must be guarded by a #ifdef MOZ_GECKO_PROFILER, *except* for the
+// following macros and functions, which encapsulate the most common operations
+// and thus avoid the need for many #ifdefs.
+
+#  define AUTO_PROFILER_INIT ::profiler_init_main_thread_id()
+#  define AUTO_PROFILER_INIT2
+
+// Function stubs for when MOZ_GECKO_PROFILER is not defined.
+
+static inline void profiler_init(void* stackTop) {}
+
+static inline void profiler_shutdown(
+    IsFastShutdown aIsFastShutdown = IsFastShutdown::No) {}
+
+#else  // !MOZ_GECKO_PROFILER
+
+#  include "BaseProfiler.h"
+#  include "mozilla/Attributes.h"
+#  include "mozilla/Maybe.h"
+#  include "mozilla/MozPromise.h"
+#  include "mozilla/PowerOfTwo.h"
+#  include "mozilla/Vector.h"
+
+//---------------------------------------------------------------------------
+// Start and stop the profiler
+//---------------------------------------------------------------------------
+
+static constexpr mozilla::PowerOfTwo32 PROFILER_DEFAULT_ENTRIES =
+    mozilla::baseprofiler::BASE_PROFILER_DEFAULT_ENTRIES;
+
+static constexpr mozilla::PowerOfTwo32 PROFILER_DEFAULT_STARTUP_ENTRIES =
+    mozilla::baseprofiler::BASE_PROFILER_DEFAULT_STARTUP_ENTRIES;
+
+#  define PROFILER_DEFAULT_INTERVAL BASE_PROFILER_DEFAULT_INTERVAL
+#  define PROFILER_MAX_INTERVAL BASE_PROFILER_MAX_INTERVAL
+
+#  define PROFILER_DEFAULT_ACTIVE_TAB_ID 0
+
+// Initialize the profiler. If MOZ_PROFILER_STARTUP is set the profiler will
+// also be started. This call must happen before any other profiler calls
+// (except profiler_start(), which will call profiler_init() if it hasn't
+// already run).
+void profiler_init(void* stackTop);
+void profiler_init_threadmanager();
+
+// Call this as early as possible
+#  define AUTO_PROFILER_INIT mozilla::AutoProfilerInit PROFILER_RAII
+// Call this after the nsThreadManager is Init()ed
+#  define AUTO_PROFILER_INIT2 mozilla::AutoProfilerInit2 PROFILER_RAII
+
+// Clean up the profiler module, stopping it if required. This function may
+// also save a shutdown profile if requested. No profiler calls should happen
+// after this point and all profiling stack labels should have been popped.
+void profiler_shutdown(IsFastShutdown aIsFastShutdown = IsFastShutdown::No);
+
+// Start the profiler -- initializing it first if necessary -- with the
+// selected options. Stops and restarts the profiler if it is already active.
+// After starting the profiler is "active". The samples will be recorded in a
+// circular buffer.
+//   "aCapacity" is the maximum number of 8-bytes entries in the profiler's
+//               circular buffer.
+//   "aInterval" the sampling interval, measured in millseconds.
+//   "aFeatures" is the feature set. Features unsupported by this
+//               platform/configuration are ignored.
+//   "aFilters" is the list of thread filters. Threads that do not match any
+//              of the filters are not profiled. A filter matches a thread if
+//              (a) the thread name contains the filter as a case-insensitive
+//                  substring, or
+//              (b) the filter is of the form "pid:<n>" where n is the process
+//                  id of the process that the thread is running in.
+//   "aActiveTabID" BrowserId of the active browser screen's active tab.
+//               It's being used to determine the profiled tab. It's "0" if
+//               we failed to get the ID.
+//   "aDuration" is the duration of entries in the profiler's circular buffer.
+// Returns as soon as this process' profiler has started, the returned promise
+// gets resolved when profilers in sub-processes (if any) have started.
+RefPtr<mozilla::GenericPromise> profiler_start(
+    mozilla::PowerOfTwo32 aCapacity, double aInterval, uint32_t aFeatures,
+    const char** aFilters, uint32_t aFilterCount, uint64_t aActiveTabID,
+    const mozilla::Maybe<double>& aDuration = mozilla::Nothing());
+
+// Stop the profiler and discard the profile without saving it. A no-op if the
+// profiler is inactive. After stopping the profiler is "inactive".
+// Returns as soon as this process' profiler has stopped, the returned promise
+// gets resolved when profilers in sub-processes (if any) have stopped.
+RefPtr<mozilla::GenericPromise> profiler_stop();
+
+// If the profiler is inactive, start it. If it's already active, restart it if
+// the requested settings differ from the current settings. Both the check and
+// the state change are performed while the profiler state is locked.
+// The only difference to profiler_start is that the current buffer contents are
+// not discarded if the profiler is already running with the requested settings.
+void profiler_ensure_started(
+    mozilla::PowerOfTwo32 aCapacity, double aInterval, uint32_t aFeatures,
+    const char** aFilters, uint32_t aFilterCount, uint64_t aActiveTabID,
+    const mozilla::Maybe<double>& aDuration = mozilla::Nothing());
+
+//---------------------------------------------------------------------------
+// Control the profiler
+//---------------------------------------------------------------------------
+
+// Pause and resume the profiler. No-ops if the profiler is inactive. While
+// paused the profile will not take any samples and will not record any data
+// into its buffers. The profiler remains fully initialized in this state.
+// Timeline markers will still be stored. This feature will keep JavaScript
+// profiling enabled, thus allowing toggling the profiler without invalidating
+// the JIT.
+// Returns as soon as this process' profiler has paused/resumed, the returned
+// promise gets resolved when profilers in sub-processes (if any) have
+// paused/resumed.
+RefPtr<mozilla::GenericPromise> profiler_pause();
+RefPtr<mozilla::GenericPromise> profiler_resume();
+
+// Only pause and resume the periodic sampling loop, including stack sampling,
+// counters, and profiling overheads.
+// Returns as soon as this process' profiler has paused/resumed sampling, the
+// returned promise gets resolved when profilers in sub-processes (if any) have
+// paused/resumed sampling.
+RefPtr<mozilla::GenericPromise> profiler_pause_sampling();
+RefPtr<mozilla::GenericPromise> profiler_resume_sampling();
+
+//---------------------------------------------------------------------------
+// Get information from the profiler
+//---------------------------------------------------------------------------
+
+// Get the params used to start the profiler. Returns 0 and an empty vector
+// (via outparams) if the profile is inactive. It's possible that the features
+// returned may be slightly different to those requested due to required
+// adjustments.
+void profiler_get_start_params(
+    int* aEntrySize, mozilla::Maybe<double>* aDuration, double* aInterval,
+    uint32_t* aFeatures,
+    mozilla::Vector<const char*, 0, mozilla::MallocAllocPolicy>* aFilters,
+    uint64_t* aActiveTabID);
+
+//---------------------------------------------------------------------------
+// RAII classes
+//---------------------------------------------------------------------------
+
+namespace mozilla {
+
+class MOZ_RAII AutoProfilerInit {
+ public:
+  explicit AutoProfilerInit() { profiler_init(this); }
+
+  ~AutoProfilerInit() { profiler_shutdown(); }
+
+ private:
+};
+
+class MOZ_RAII AutoProfilerInit2 {
+ public:
+  explicit AutoProfilerInit2() { profiler_init_threadmanager(); }
+
+ private:
+};
+
+}  // namespace mozilla
+
+#endif  // !MOZ_GECKO_PROFILER
+
+#endif  // ProfilerControl_h
diff --git a/tools/profiler/public/ProfilerCounts.h b/tools/profiler/public/ProfilerCounts.h
new file mode 100644
index 0000000000..86f6cbfe4f
--- /dev/null
+++ b/tools/profiler/public/ProfilerCounts.h
@@ -0,0 +1,296 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerCounts_h
+#define ProfilerCounts_h
+
+#ifndef MOZ_GECKO_PROFILER
+
+#  define PROFILER_DEFINE_COUNT_TOTAL(label, category, description)
+#  define PROFILER_DEFINE_COUNT(label, category, description)
+#  define PROFILER_DEFINE_STATIC_COUNT_TOTAL(label, category, description)
+#  define AUTO_PROFILER_TOTAL(label, count)
+#  define AUTO_PROFILER_COUNT(label)
+#  define AUTO_PROFILER_STATIC_COUNT(label, count)
+
+#else
+
+#  include "mozilla/Atomics.h"
+
+class BaseProfilerCount;
+void profiler_add_sampled_counter(BaseProfilerCount* aCounter);
+void profiler_remove_sampled_counter(BaseProfilerCount* aCounter);
+
+typedef mozilla::Atomic<int64_t, mozilla::MemoryOrdering::Relaxed>
+    ProfilerAtomicSigned;
+typedef mozilla::Atomic<uint64_t, mozilla::MemoryOrdering::Relaxed>
+    ProfilerAtomicUnsigned;
+
+// Counter support
+// There are two types of counters:
+// 1) a simple counter which can be added to or subtracted from.  This could
+// track the number of objects of a type, the number of calls to something
+// (reflow, JIT, etc).
+// 2) a combined counter which has the above, plus a number-of-calls counter
+// that is incremented by 1 for each call to modify the count.  This provides
+// an optional source for a 'heatmap' of access.  This can be used (for
+// example) to track the amount of memory allocated, and provide a heatmap of
+// memory operations (allocs/frees).
+//
+// Counters are sampled by the profiler once per sample-period.  At this time,
+// all counters are global to the process.  In the future, there might be more
+// versions with per-thread or other discriminators.
+//
+// Typical usage:
+// There are two ways to use counters: With heap-created counter objects,
+// or using macros.  Note: the macros use statics, and will be slightly
+// faster/smaller, and you need to care about creating them before using
+// them.  They're similar to the use-pattern for the other AUTO_PROFILER*
+// macros, but they do need the PROFILER_DEFINE* to be use to instantiate
+// the statics.
+//
+// PROFILER_DEFINE_COUNT(mything, "JIT", "Some JIT byte count")
+// ...
+// void foo() { ... AUTO_PROFILER_COUNT(mything, number_of_bytes_used); ... }
+//
+// or (to also get a heatmap)
+//
+// PROFILER_DEFINE_COUNT_TOTAL(mything, "JIT", "Some JIT byte count")
+// ...
+// void foo() {
+//   ...
+//   AUTO_PROFILER_COUNT_TOTAL(mything, number_of_bytes_generated);
+//   ...
+// }
+//
+// To use without statics/macros:
+//
+// UniquePtr<ProfilerCounter> myCounter;
+// ...
+// myCounter =
+//   MakeUnique<ProfilerCounter>("mything", "JIT", "Some JIT byte count"));
+// ...
+// void foo() { ... myCounter->Add(number_of_bytes_generated0; ... }
+
+class BaseProfilerCount {
+ public:
+  BaseProfilerCount(const char* aLabel, ProfilerAtomicSigned* aCounter,
+                    ProfilerAtomicUnsigned* aNumber, const char* aCategory,
+                    const char* aDescription)
+      : mLabel(aLabel),
+        mCategory(aCategory),
+        mDescription(aDescription),
+        mCounter(aCounter),
+        mNumber(aNumber) {
+#  define COUNTER_CANARY 0xDEADBEEF
+#  ifdef DEBUG
+    mCanary = COUNTER_CANARY;
+    mPrevNumber = 0;
+#  endif
+    // Can't call profiler_* here since this may be non-xul-library
+  }
+
+  virtual ~BaseProfilerCount() {
+#  ifdef DEBUG
+    mCanary = 0;
+#  endif
+  }
+
+  struct CountSample {
+    int64_t count;
+    uint64_t number;
+    // This field indicates if the sample has already been consummed by a call
+    // to the Sample() method. This allows the profiler to discard duplicate
+    // samples if the counter sampling rate is lower than the profiler sampling
+    // rate. This can happen for example with some power meters that sample up
+    // to every 10ms.
+    // It should always be true when calling Sample() for the first time.
+    bool isSampleNew;
+  };
+  virtual CountSample Sample() {
+    MOZ_ASSERT(mCanary == COUNTER_CANARY);
+
+    CountSample result;
+    result.count = *mCounter;
+    result.number = mNumber ? *mNumber : 0;
+#  ifdef DEBUG
+    MOZ_ASSERT(result.number >= mPrevNumber);
+    mPrevNumber = result.number;
+#  endif
+    result.isSampleNew = true;
+    return result;
+  }
+
+  void Clear() {
+    *mCounter = 0;
+    // We don't reset *mNumber or mPrevNumber.  We encode numbers as
+    // positive deltas, and currently we only care about the deltas (for
+    // e.g. heatmaps).  If we ever need to clear mNumber as well, we can an
+    // alternative method (Reset()) to do so.
+  }
+
+  // We don't define ++ and Add() here, since the static defines directly
+  // increment the atomic counters, and the subclasses implement ++ and
+  // Add() directly.
+
+  // These typically are static strings (for example if you use the macros
+  // below)
+  const char* mLabel;
+  const char* mCategory;
+  const char* mDescription;
+  // We're ok with these being un-ordered in race conditions.  These are
+  // pointers because we want to be able to use statics and increment them
+  // directly.  Otherwise we could just have them inline, and not need the
+  // constructor args.
+  // These can be static globals (using the macros below), though they
+  // don't have to be - their lifetime must be longer than the use of them
+  // by the profiler (see profiler_add/remove_sampled_counter()).  If you're
+  // using a lot of these, they probably should be allocated at runtime (see
+  // class ProfilerCountOnly below).
+  ProfilerAtomicSigned* mCounter;
+  ProfilerAtomicUnsigned* mNumber;  // may be null
+
+#  ifdef DEBUG
+  uint32_t mCanary;
+  uint64_t mPrevNumber;  // value of number from the last Sample()
+#  endif
+};
+
+// Designed to be allocated dynamically, and simply incremented with obj++
+// or obj->Add(n)
+class ProfilerCounter final : public BaseProfilerCount {
+ public:
+  ProfilerCounter(const char* aLabel, const char* aCategory,
+                  const char* aDescription)
+      : BaseProfilerCount(aLabel, &mCounter, nullptr, aCategory, aDescription) {
+    // Assume we're in libxul
+    profiler_add_sampled_counter(this);
+  }
+
+  virtual ~ProfilerCounter() { profiler_remove_sampled_counter(this); }
+
+  BaseProfilerCount& operator++() {
+    Add(1);
+    return *this;
+  }
+
+  void Add(int64_t aNumber) { mCounter += aNumber; }
+
+  ProfilerAtomicSigned mCounter;
+};
+
+// Also keeps a heatmap (number of calls to ++/Add())
+class ProfilerCounterTotal final : public BaseProfilerCount {
+ public:
+  ProfilerCounterTotal(const char* aLabel, const char* aCategory,
+                       const char* aDescription)
+      : BaseProfilerCount(aLabel, &mCounter, &mNumber, aCategory,
+                          aDescription) {
+    // Assume we're in libxul
+    profiler_add_sampled_counter(this);
+  }
+
+  virtual ~ProfilerCounterTotal() { profiler_remove_sampled_counter(this); }
+
+  BaseProfilerCount& operator++() {
+    Add(1);
+    return *this;
+  }
+
+  void Add(int64_t aNumber) {
+    mCounter += aNumber;
+    mNumber++;
+  }
+
+  ProfilerAtomicSigned mCounter;
+  ProfilerAtomicUnsigned mNumber;
+};
+
+// Defines a counter that is sampled on each profiler tick, with a running
+// count (signed), and number-of-instances. Note that because these are two
+// independent Atomics, there is a possiblity that count will not include
+// the last call, but number of uses will.  I think this is not worth
+// worrying about
+#  define PROFILER_DEFINE_COUNT_TOTAL(label, category, description) \
+    ProfilerAtomicSigned profiler_count_##label(0);                 \
+    ProfilerAtomicUnsigned profiler_number_##label(0);              \
+    const char profiler_category_##label[] = category;              \
+    const char profiler_description_##label[] = description;        \
+    mozilla::UniquePtr<BaseProfilerCount> AutoCount_##label;
+
+// This counts, but doesn't keep track of the number of calls to
+// AUTO_PROFILER_COUNT()
+#  define PROFILER_DEFINE_COUNT(label, category, description) \
+    ProfilerAtomicSigned profiler_count_##label(0);           \
+    const char profiler_category_##label[] = category;        \
+    const char profiler_description_##label[] = description;  \
+    mozilla::UniquePtr<BaseProfilerCount> AutoCount_##label;
+
+// This will create a static initializer if used, but avoids a possible
+// allocation.
+#  define PROFILER_DEFINE_STATIC_COUNT_TOTAL(label, category, description)  \
+    ProfilerAtomicSigned profiler_count_##label(0);                         \
+    ProfilerAtomicUnsigned profiler_number_##label(0);                      \
+    BaseProfilerCount AutoCount_##label(#label, &profiler_count_##label,    \
+                                        &profiler_number_##label, category, \
+                                        description);
+
+// If we didn't care about static initializers, we could avoid the need for
+// a ptr to the BaseProfilerCount object.
+
+// XXX It would be better to do this without the if() and without the
+// theoretical race to set the UniquePtr (i.e. possible leak).
+#  define AUTO_PROFILER_COUNT_TOTAL(label, count)                           \
+    do {                                                                    \
+      profiler_number_##label++; /* do this first*/                         \
+      profiler_count_##label += count;                                      \
+      if (!AutoCount_##label) {                                             \
+        /* Ignore that we could call this twice in theory, and that we leak \
+         * them                                                             \
+         */                                                                 \
+        AutoCount_##label.reset(new BaseProfilerCount(                      \
+            #label, &profiler_count_##label, &profiler_number_##label,      \
+            profiler_category_##label, profiler_description_##label));      \
+        profiler_add_sampled_counter(AutoCount_##label.get());              \
+      }                                                                     \
+    } while (0)
+
+#  define AUTO_PROFILER_COUNT(label, count)                                 \
+    do {                                                                    \
+      profiler_count_##label += count; /* do this first*/                   \
+      if (!AutoCount_##label) {                                             \
+        /* Ignore that we could call this twice in theory, and that we leak \
+         * them                                                             \
+         */                                                                 \
+        AutoCount_##label.reset(new BaseProfilerCount(                      \
+            #label, nullptr, &profiler_number_##label,                      \
+            profiler_category_##label, profiler_description_##label));      \
+        profiler_add_sampled_counter(AutoCount_##label.get());              \
+      }                                                                     \
+    } while (0)
+
+#  define AUTO_PROFILER_STATIC_COUNT(label, count)  \
+    do {                                            \
+      profiler_number_##label++; /* do this first*/ \
+      profiler_count_##label += count;              \
+    } while (0)
+
+// if we need to force the allocation
+#  define AUTO_PROFILER_FORCE_ALLOCATION(label)                             \
+    do {                                                                    \
+      if (!AutoCount_##label) {                                             \
+        /* Ignore that we could call this twice in theory, and that we leak \
+         * them                                                             \
+         */                                                                 \
+        AutoCount_##label.reset(new BaseProfilerCount(                      \
+            #label, &profiler_count_##label, &profiler_number_##label,      \
+            profiler_category_##label, profiler_description_##label));      \
+      }                                                                     \
+    } while (0)
+
+#endif  // !MOZ_GECKO_PROFILER
+
+#endif  // ProfilerCounts_h
diff --git a/tools/profiler/public/ProfilerLabels.h b/tools/profiler/public/ProfilerLabels.h
new file mode 100644
index 0000000000..f05e357451
--- /dev/null
+++ b/tools/profiler/public/ProfilerLabels.h
@@ -0,0 +1,268 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This header contains all definitions related to profiler labels.
+// It is safe to include unconditionally, and only defines empty macros if
+// MOZ_GECKO_PROFILER is not set.
+
+#ifndef ProfilerLabels_h
+#define ProfilerLabels_h
+
+#include "mozilla/ProfilerThreadState.h"
+
+#include "js/ProfilingCategory.h"
+#include "js/ProfilingStack.h"
+#include "js/RootingAPI.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/BaseProfilerRAIIMacro.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/ProfilerThreadRegistration.h"
+#include "mozilla/ThreadLocal.h"
+#include "nsString.h"
+
+#include <stdint.h>
+
+struct JSContext;
+
+// Insert an RAII object in this scope to enter a label stack frame. Any
+// samples collected in this scope will contain this label in their stack.
+// The label argument must be a static C string. It is usually of the
+// form "ClassName::FunctionName". (Ideally we'd use the compiler to provide
+// that for us, but __func__ gives us the function name without the class
+// name.) If the label applies to only part of a function, you can qualify it
+// like this: "ClassName::FunctionName:PartName".
+//
+// Use AUTO_PROFILER_LABEL_DYNAMIC_* if you want to add additional / dynamic
+// information to the label stack frame.
+#define AUTO_PROFILER_LABEL(label, categoryPair) \
+  mozilla::AutoProfilerLabel PROFILER_RAII(      \
+      label, nullptr, JS::ProfilingCategoryPair::categoryPair)
+
+// Similar to AUTO_PROFILER_LABEL, but that adds the RELEVANT_FOR_JS flag.
+#define AUTO_PROFILER_LABEL_RELEVANT_FOR_JS(label, categoryPair) \
+  mozilla::AutoProfilerLabel PROFILER_RAII(                      \
+      label, nullptr, JS::ProfilingCategoryPair::categoryPair,   \
+      uint32_t(js::ProfilingStackFrame::Flags::RELEVANT_FOR_JS))
+
+// Similar to AUTO_PROFILER_LABEL, but with only one argument: the category
+// pair. The label string is taken from the category pair. This is convenient
+// for labels like AUTO_PROFILER_LABEL_CATEGORY_PAIR(GRAPHICS_LayerBuilding)
+// which would otherwise just repeat the string.
+#define AUTO_PROFILER_LABEL_CATEGORY_PAIR(categoryPair)     \
+  mozilla::AutoProfilerLabel PROFILER_RAII(                 \
+      "", nullptr, JS::ProfilingCategoryPair::categoryPair, \
+      uint32_t(                                             \
+          js::ProfilingStackFrame::Flags::LABEL_DETERMINED_BY_CATEGORY_PAIR))
+
+// Similar to AUTO_PROFILER_LABEL_CATEGORY_PAIR but adding the RELEVANT_FOR_JS
+// flag.
+#define AUTO_PROFILER_LABEL_CATEGORY_PAIR_RELEVANT_FOR_JS(categoryPair)        \
+  mozilla::AutoProfilerLabel PROFILER_RAII(                                    \
+      "", nullptr, JS::ProfilingCategoryPair::categoryPair,                    \
+      uint32_t(                                                                \
+          js::ProfilingStackFrame::Flags::LABEL_DETERMINED_BY_CATEGORY_PAIR) | \
+          uint32_t(js::ProfilingStackFrame::Flags::RELEVANT_FOR_JS))
+
+// Similar to AUTO_PROFILER_LABEL, but with an additional string. The inserted
+// RAII object stores the cStr pointer in a field; it does not copy the string.
+//
+// WARNING: This means that the string you pass to this macro needs to live at
+// least until the end of the current scope. Be careful using this macro with
+// ns[C]String; the other AUTO_PROFILER_LABEL_DYNAMIC_* macros below are
+// preferred because they avoid this problem.
+//
+// If the profiler samples the current thread and walks the label stack while
+// this RAII object is on the stack, it will copy the supplied string into the
+// profile buffer. So there's one string copy operation, and it happens at
+// sample time.
+//
+// Compare this to the plain AUTO_PROFILER_LABEL macro, which only accepts
+// literal strings: When the label stack frames generated by
+// AUTO_PROFILER_LABEL are sampled, no string copy needs to be made because the
+// profile buffer can just store the raw pointers to the literal strings.
+// Consequently, AUTO_PROFILER_LABEL frames take up considerably less space in
+// the profile buffer than AUTO_PROFILER_LABEL_DYNAMIC_* frames.
+#define AUTO_PROFILER_LABEL_DYNAMIC_CSTR(label, categoryPair, cStr) \
+  mozilla::AutoProfilerLabel PROFILER_RAII(                         \
+      label, cStr, JS::ProfilingCategoryPair::categoryPair)
+
+// Like AUTO_PROFILER_LABEL_DYNAMIC_CSTR, but with the NONSENSITIVE flag to
+// note that it does not contain sensitive information (so we can include it
+// in, for example, the BackgroundHangMonitor)
+#define AUTO_PROFILER_LABEL_DYNAMIC_CSTR_NONSENSITIVE(label, categoryPair, \
+                                                      cStr)                \
+  mozilla::AutoProfilerLabel PROFILER_RAII(                                \
+      label, cStr, JS::ProfilingCategoryPair::categoryPair,                \
+      uint32_t(js::ProfilingStackFrame::Flags::NONSENSITIVE))
+
+// Similar to AUTO_PROFILER_LABEL_DYNAMIC_CSTR, but takes an nsACString.
+//
+// Note: The use of the Maybe<>s ensures the scopes for the dynamic string and
+// the AutoProfilerLabel are appropriate, while also not incurring the runtime
+// cost of the string assignment unless the profiler is active. Therefore,
+// unlike AUTO_PROFILER_LABEL and AUTO_PROFILER_LABEL_DYNAMIC_CSTR, this macro
+// doesn't push/pop a label when the profiler is inactive.
+#define AUTO_PROFILER_LABEL_DYNAMIC_NSCSTRING(label, categoryPair, nsCStr) \
+  mozilla::Maybe<nsAutoCString> autoCStr;                                  \
+  mozilla::Maybe<mozilla::AutoProfilerLabel> raiiObjectNsCString;          \
+  if (profiler_is_active()) {                                              \
+    autoCStr.emplace(nsCStr);                                              \
+    raiiObjectNsCString.emplace(label, autoCStr->get(),                    \
+                                JS::ProfilingCategoryPair::categoryPair);  \
+  }
+
+#define AUTO_PROFILER_LABEL_DYNAMIC_NSCSTRING_RELEVANT_FOR_JS(           \
+    label, categoryPair, nsCStr)                                         \
+  mozilla::Maybe<nsAutoCString> autoCStr;                                \
+  mozilla::Maybe<mozilla::AutoProfilerLabel> raiiObjectNsCString;        \
+  if (profiler_is_active()) {                                            \
+    autoCStr.emplace(nsCStr);                                            \
+    raiiObjectNsCString.emplace(                                         \
+        label, autoCStr->get(), JS::ProfilingCategoryPair::categoryPair, \
+        uint32_t(js::ProfilingStackFrame::Flags::RELEVANT_FOR_JS));      \
+  }
+
+// Match the conditions for MOZ_ENABLE_BACKGROUND_HANG_MONITOR
+#if defined(NIGHTLY_BUILD) && !defined(MOZ_DEBUG) && !defined(MOZ_TSAN) && \
+    !defined(MOZ_ASAN)
+#  define SHOULD_CREATE_ALL_NONSENSITIVE_LABEL_FRAMES true
+#else
+#  define SHOULD_CREATE_ALL_NONSENSITIVE_LABEL_FRAMES profiler_is_active()
+#endif
+
+// See note above AUTO_PROFILER_LABEL_DYNAMIC_CSTR_NONSENSITIVE
+#define AUTO_PROFILER_LABEL_DYNAMIC_NSCSTRING_NONSENSITIVE(              \
+    label, categoryPair, nsCStr)                                         \
+  mozilla::Maybe<nsAutoCString> autoCStr;                                \
+  mozilla::Maybe<mozilla::AutoProfilerLabel> raiiObjectNsCString;        \
+  if (SHOULD_CREATE_ALL_NONSENSITIVE_LABEL_FRAMES) {                     \
+    autoCStr.emplace(nsCStr);                                            \
+    raiiObjectNsCString.emplace(                                         \
+        label, autoCStr->get(), JS::ProfilingCategoryPair::categoryPair, \
+        uint32_t(js::ProfilingStackFrame::Flags::NONSENSITIVE));         \
+  }
+
+// Similar to AUTO_PROFILER_LABEL_DYNAMIC_CSTR, but takes an nsString that is
+// is lossily converted to an ASCII string.
+//
+// Note: The use of the Maybe<>s ensures the scopes for the converted dynamic
+// string and the AutoProfilerLabel are appropriate, while also not incurring
+// the runtime cost of the string conversion unless the profiler is active.
+// Therefore, unlike AUTO_PROFILER_LABEL and AUTO_PROFILER_LABEL_DYNAMIC_CSTR,
+// this macro doesn't push/pop a label when the profiler is inactive.
+#define AUTO_PROFILER_LABEL_DYNAMIC_LOSSY_NSSTRING(label, categoryPair, nsStr) \
+  mozilla::Maybe<NS_LossyConvertUTF16toASCII> asciiStr;                        \
+  mozilla::Maybe<mozilla::AutoProfilerLabel> raiiObjectLossyNsString;          \
+  if (profiler_is_active()) {                                                  \
+    asciiStr.emplace(nsStr);                                                   \
+    raiiObjectLossyNsString.emplace(label, asciiStr->get(),                    \
+                                    JS::ProfilingCategoryPair::categoryPair);  \
+  }
+
+// Similar to AUTO_PROFILER_LABEL, but accepting a JSContext* parameter, and a
+// no-op if the profiler is disabled.
+// Used to annotate functions for which overhead in the range of nanoseconds is
+// noticeable. It avoids overhead from the TLS lookup because it can get the
+// ProfilingStack from the JS context, and avoids almost all overhead in the
+// case where the profiler is disabled.
+#define AUTO_PROFILER_LABEL_FAST(label, categoryPair, ctx) \
+  mozilla::AutoProfilerLabel PROFILER_RAII(                \
+      ctx, label, nullptr, JS::ProfilingCategoryPair::categoryPair)
+
+// Similar to AUTO_PROFILER_LABEL_FAST, but also takes an extra string and an
+// additional set of flags. The flags parameter should carry values from the
+// js::ProfilingStackFrame::Flags enum.
+#define AUTO_PROFILER_LABEL_DYNAMIC_FAST(label, dynamicString, categoryPair, \
+                                         ctx, flags)                         \
+  mozilla::AutoProfilerLabel PROFILER_RAII(                                  \
+      ctx, label, dynamicString, JS::ProfilingCategoryPair::categoryPair,    \
+      flags)
+
+namespace mozilla {
+
+#ifndef MOZ_GECKO_PROFILER
+
+class MOZ_RAII AutoProfilerLabel {
+ public:
+  // This is the AUTO_PROFILER_LABEL and AUTO_PROFILER_LABEL_DYNAMIC variant.
+  AutoProfilerLabel(const char* aLabel, const char* aDynamicString,
+                    JS::ProfilingCategoryPair aCategoryPair,
+                    uint32_t aFlags = 0) {}
+
+  // This is the AUTO_PROFILER_LABEL_FAST variant.
+  AutoProfilerLabel(JSContext* aJSContext, const char* aLabel,
+                    const char* aDynamicString,
+                    JS::ProfilingCategoryPair aCategoryPair, uint32_t aFlags) {}
+
+  ~AutoProfilerLabel() {}
+};
+
+#else  // !MOZ_GECKO_PROFILER
+
+// This class creates a non-owning ProfilingStack reference. Objects of this
+// class are stack-allocated, and so exist within a thread, and are thus bounded
+// by the lifetime of the thread, which ensures that the references held can't
+// be used after the ProfilingStack is destroyed.
+class MOZ_RAII AutoProfilerLabel {
+ public:
+  // This is the AUTO_PROFILER_LABEL and AUTO_PROFILER_LABEL_DYNAMIC variant.
+  AutoProfilerLabel(const char* aLabel, const char* aDynamicString,
+                    JS::ProfilingCategoryPair aCategoryPair,
+                    uint32_t aFlags = 0) {
+    // Get the ProfilingStack from TLS.
+    ProfilingStack* profilingStack =
+        profiler::ThreadRegistration::WithOnThreadRefOr(
+            [](profiler::ThreadRegistration::OnThreadRef aThread) {
+              return &aThread.UnlockedConstReaderAndAtomicRWRef()
+                          .ProfilingStackRef();
+            },
+            nullptr);
+    Push(profilingStack, aLabel, aDynamicString, aCategoryPair, aFlags);
+  }
+
+  // This is the AUTO_PROFILER_LABEL_FAST variant. It retrieves the
+  // ProfilingStack from the JSContext and does nothing if the profiler is
+  // inactive.
+  AutoProfilerLabel(JSContext* aJSContext, const char* aLabel,
+                    const char* aDynamicString,
+                    JS::ProfilingCategoryPair aCategoryPair, uint32_t aFlags) {
+    Push(js::GetContextProfilingStackIfEnabled(aJSContext), aLabel,
+         aDynamicString, aCategoryPair, aFlags);
+  }
+
+  void Push(ProfilingStack* aProfilingStack, const char* aLabel,
+            const char* aDynamicString, JS::ProfilingCategoryPair aCategoryPair,
+            uint32_t aFlags = 0) {
+    // This function runs both on and off the main thread.
+
+    mProfilingStack = aProfilingStack;
+    if (mProfilingStack) {
+      mProfilingStack->pushLabelFrame(aLabel, aDynamicString, this,
+                                      aCategoryPair, aFlags);
+    }
+  }
+
+  ~AutoProfilerLabel() {
+    // This function runs both on and off the main thread.
+
+    if (mProfilingStack) {
+      mProfilingStack->pop();
+    }
+  }
+
+ private:
+  // We save a ProfilingStack pointer in the ctor so we don't have to redo the
+  // TLS lookup in the dtor.
+  ProfilingStack* mProfilingStack;
+};
+
+#endif  // !MOZ_GECKO_PROFILER
+
+}  // namespace mozilla
+
+#endif  // ProfilerLabels_h
diff --git a/tools/profiler/public/ProfilerMarkerTypes.h b/tools/profiler/public/ProfilerMarkerTypes.h
new file mode 100644
index 0000000000..0868c70e30
--- /dev/null
+++ b/tools/profiler/public/ProfilerMarkerTypes.h
@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerMarkerTypes_h
+#define ProfilerMarkerTypes_h
+
+// This header contains common marker type definitions that rely on xpcom.
+//
+// It #include's "mozilla/BaseProfilerMarkerTypess.h" and "ProfilerMarkers.h",
+// see these files for more marker types, how to define other marker types, and
+// how to add markers to the profiler buffers.
+
+// !!!                       /!\ WORK IN PROGRESS /!\                       !!!
+// This file contains draft marker definitions, but most are not used yet.
+// Further work is needed to complete these definitions, and use them to convert
+// existing PROFILER_ADD_MARKER calls. See meta bug 1661394.
+
+#include "mozilla/BaseProfilerMarkerTypes.h"
+#include "mozilla/ProfilerMarkers.h"
+#include "js/ProfilingFrameIterator.h"
+#include "js/Utility.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/ServoTraversalStatistics.h"
+
+namespace geckoprofiler::markers {
+
+// Import some common markers from mozilla::baseprofiler::markers.
+using MediaSampleMarker = mozilla::baseprofiler::markers::MediaSampleMarker;
+using VideoFallingBehindMarker =
+    mozilla::baseprofiler::markers::VideoFallingBehindMarker;
+using ContentBuildMarker = mozilla::baseprofiler::markers::ContentBuildMarker;
+using MediaEngineMarker = mozilla::baseprofiler::markers::MediaEngineMarker;
+using MediaEngineTextMarker =
+    mozilla::baseprofiler::markers::MediaEngineTextMarker;
+
+}  // namespace geckoprofiler::markers
+
+#endif  // ProfilerMarkerTypes_h
diff --git a/tools/profiler/public/ProfilerMarkers.h b/tools/profiler/public/ProfilerMarkers.h
new file mode 100644
index 0000000000..ca53c3f189
--- /dev/null
+++ b/tools/profiler/public/ProfilerMarkers.h
@@ -0,0 +1,355 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Markers are useful to delimit something important happening such as the first
+// paint. Unlike labels, which are only recorded in the profile buffer if a
+// sample is collected while the label is on the label stack, markers will
+// always be recorded in the profile buffer.
+//
+// This header contains definitions necessary to add markers to the Gecko
+// Profiler buffer.
+//
+// It #include's "mozilla/BaseProfilerMarkers.h", see that header for base
+// definitions necessary to create marker types.
+//
+// If common marker types are needed, #include "ProfilerMarkerTypes.h" instead.
+//
+// But if you want to create your own marker type locally, you can #include this
+// header only; look at ProfilerMarkerTypes.h for examples of how to define
+// types.
+//
+// To then record markers:
+// - Use `baseprofiler::AddMarker(...)` from mozglue or other libraries that are
+//   outside of xul, especially if they may happen outside of xpcom's lifetime
+//   (typically startup, shutdown, or tests).
+// - Otherwise #include "ProfilerMarkers.h" instead, and use
+//   `profiler_add_marker(...)`.
+// See these functions for more details.
+
+#ifndef ProfilerMarkers_h
+#define ProfilerMarkers_h
+
+#include "mozilla/BaseProfilerMarkers.h"
+#include "mozilla/ProfilerMarkersDetail.h"
+#include "mozilla/ProfilerLabels.h"
+#include "nsJSUtils.h"  // for nsJSUtils::GetCurrentlyRunningCodeInnerWindowID
+
+class nsIDocShell;
+
+namespace geckoprofiler::markers::detail {
+// Please do not use anything from the detail namespace outside the profiler.
+
+#ifdef MOZ_GECKO_PROFILER
+mozilla::Maybe<uint64_t> profiler_get_inner_window_id_from_docshell(
+    nsIDocShell* aDocshell);
+#else
+inline mozilla::Maybe<uint64_t> profiler_get_inner_window_id_from_docshell(
+    nsIDocShell* aDocshell) {
+  return mozilla::Nothing();
+}
+#endif  // MOZ_GECKO_PROFILER
+
+}  // namespace geckoprofiler::markers::detail
+
+// This is a helper function to get the Inner Window ID from DocShell but it's
+// not a recommended method to get it and it's not encouraged to use this
+// function. If there is a computed inner window ID, `window`, or `Document`
+// available in the call site, please use them. Use this function as a last
+// resort.
+inline mozilla::MarkerInnerWindowId MarkerInnerWindowIdFromDocShell(
+    nsIDocShell* aDocshell) {
+  mozilla::Maybe<uint64_t> id = geckoprofiler::markers::detail::
+      profiler_get_inner_window_id_from_docshell(aDocshell);
+  if (!id) {
+    return mozilla::MarkerInnerWindowId::NoId();
+  }
+  return mozilla::MarkerInnerWindowId(*id);
+}
+
+// This is a helper function to get the Inner Window ID from a JS Context but
+// it's not a recommended method to get it and it's not encouraged to use this
+// function. If there is a computed inner window ID, `window`, or `Document`
+// available in the call site, please use them. Use this function as a last
+// resort.
+inline mozilla::MarkerInnerWindowId MarkerInnerWindowIdFromJSContext(
+    JSContext* aContext) {
+  return mozilla::MarkerInnerWindowId(
+      nsJSUtils::GetCurrentlyRunningCodeInnerWindowID(aContext));
+}
+
+// Bring category names from Base Profiler into the geckoprofiler::category
+// namespace, for consistency with other Gecko Profiler identifiers.
+namespace geckoprofiler::category {
+using namespace ::mozilla::baseprofiler::category;
+}
+
+#ifdef MOZ_GECKO_PROFILER
+// Forward-declaration. TODO: Move to more common header, see bug 1681416.
+bool profiler_capture_backtrace_into(
+    mozilla::ProfileChunkedBuffer& aChunkedBuffer,
+    mozilla::StackCaptureOptions aCaptureOptions);
+
+// Add a marker to a given buffer. `AddMarker()` and related macros should be
+// used in most cases, see below for more information about them and the
+// paramters; This function may be useful when markers need to be recorded in a
+// local buffer outside of the main profiler buffer.
+template <typename MarkerType, typename... PayloadArguments>
+mozilla::ProfileBufferBlockIndex AddMarkerToBuffer(
+    mozilla::ProfileChunkedBuffer& aBuffer,
+    const mozilla::ProfilerString8View& aName,
+    const mozilla::MarkerCategory& aCategory, mozilla::MarkerOptions&& aOptions,
+    MarkerType aMarkerType, const PayloadArguments&... aPayloadArguments) {
+  AUTO_PROFILER_LABEL("AddMarkerToBuffer", PROFILER);
+  mozilla::Unused << aMarkerType;  // Only the empty object type is useful.
+  return mozilla::base_profiler_markers_detail::AddMarkerToBuffer<MarkerType>(
+      aBuffer, aName, aCategory, std::move(aOptions),
+      profiler_active_without_feature(ProfilerFeature::NoMarkerStacks)
+          ? ::profiler_capture_backtrace_into
+          : nullptr,
+      aPayloadArguments...);
+}
+
+// Add a marker (without payload) to a given buffer.
+inline mozilla::ProfileBufferBlockIndex AddMarkerToBuffer(
+    mozilla::ProfileChunkedBuffer& aBuffer,
+    const mozilla::ProfilerString8View& aName,
+    const mozilla::MarkerCategory& aCategory,
+    mozilla::MarkerOptions&& aOptions = {}) {
+  return AddMarkerToBuffer(aBuffer, aName, aCategory, std::move(aOptions),
+                           mozilla::baseprofiler::markers::NoPayload{});
+}
+#endif
+
+[[nodiscard]] inline bool profiler_thread_is_being_profiled_for_markers() {
+  return profiler_thread_is_being_profiled(ThreadProfilingFeatures::Markers);
+}
+
+[[nodiscard]] inline bool profiler_thread_is_being_profiled_for_markers(
+    const ProfilerThreadId& aThreadId) {
+  return profiler_thread_is_being_profiled(aThreadId,
+                                           ThreadProfilingFeatures::Markers);
+}
+
+// Add a marker to the Gecko Profiler buffer.
+// - aName: Main name of this marker.
+// - aCategory: Category for this marker.
+// - aOptions: Optional settings (such as timing, inner window id,
+//   backtrace...), see `MarkerOptions` for details.
+// - aMarkerType: Empty object that specifies the type of marker.
+// - aPayloadArguments: Arguments expected by this marker type's
+// ` StreamJSONMarkerData` function.
+template <typename MarkerType, typename... PayloadArguments>
+mozilla::ProfileBufferBlockIndex profiler_add_marker(
+    const mozilla::ProfilerString8View& aName,
+    const mozilla::MarkerCategory& aCategory, mozilla::MarkerOptions&& aOptions,
+    MarkerType aMarkerType, const PayloadArguments&... aPayloadArguments) {
+#ifndef MOZ_GECKO_PROFILER
+  return {};
+#else
+  if (!profiler_thread_is_being_profiled_for_markers(
+          aOptions.ThreadId().ThreadId())) {
+    return {};
+  }
+  AUTO_PROFILER_LABEL("profiler_add_marker", PROFILER);
+  return ::AddMarkerToBuffer(profiler_get_core_buffer(), aName, aCategory,
+                             std::move(aOptions), aMarkerType,
+                             aPayloadArguments...);
+#endif
+}
+
+// Add a marker (without payload) to the Gecko Profiler buffer.
+inline mozilla::ProfileBufferBlockIndex profiler_add_marker(
+    const mozilla::ProfilerString8View& aName,
+    const mozilla::MarkerCategory& aCategory,
+    mozilla::MarkerOptions&& aOptions = {}) {
+  return profiler_add_marker(aName, aCategory, std::move(aOptions),
+                             mozilla::baseprofiler::markers::NoPayload{});
+}
+
+// Same as `profiler_add_marker()` (without payload). This macro is safe to use
+// even if MOZ_GECKO_PROFILER is not #defined.
+#define PROFILER_MARKER_UNTYPED(markerName, categoryName, ...)                 \
+  do {                                                                         \
+    AUTO_PROFILER_STATS(PROFILER_MARKER_UNTYPED);                              \
+    ::profiler_add_marker(markerName, ::geckoprofiler::category::categoryName, \
+                          ##__VA_ARGS__);                                      \
+  } while (false)
+
+// Same as `profiler_add_marker()` (with payload). This macro is safe to use
+// even if MOZ_GECKO_PROFILER is not #defined.
+#define PROFILER_MARKER(markerName, categoryName, options, MarkerType, ...)    \
+  do {                                                                         \
+    AUTO_PROFILER_STATS(PROFILER_MARKER_with_##MarkerType);                    \
+    ::profiler_add_marker(markerName, ::geckoprofiler::category::categoryName, \
+                          options, ::geckoprofiler::markers::MarkerType{},     \
+                          ##__VA_ARGS__);                                      \
+  } while (false)
+
+namespace geckoprofiler::markers {
+// Most common marker types. Others are in ProfilerMarkerTypes.h.
+using TextMarker = ::mozilla::baseprofiler::markers::TextMarker;
+using Tracing = mozilla::baseprofiler::markers::Tracing;
+}  // namespace geckoprofiler::markers
+
+// Add a text marker. This macro is safe to use even if MOZ_GECKO_PROFILER is
+// not #defined.
+#define PROFILER_MARKER_TEXT(markerName, categoryName, options, text)          \
+  do {                                                                         \
+    AUTO_PROFILER_STATS(PROFILER_MARKER_TEXT);                                 \
+    ::profiler_add_marker(markerName, ::geckoprofiler::category::categoryName, \
+                          options, ::geckoprofiler::markers::TextMarker{},     \
+                          text);                                               \
+  } while (false)
+
+// RAII object that adds a PROFILER_MARKER_TEXT when destroyed; the marker's
+// timing will be the interval from construction (unless an instant or start
+// time is already specified in the provided options) until destruction.
+class MOZ_RAII AutoProfilerTextMarker {
+ public:
+  AutoProfilerTextMarker(const char* aMarkerName,
+                         const mozilla::MarkerCategory& aCategory,
+                         mozilla::MarkerOptions&& aOptions,
+                         const nsACString& aText)
+      : mMarkerName(aMarkerName),
+        mCategory(aCategory),
+        mOptions(std::move(aOptions)),
+        mText(aText) {
+    MOZ_ASSERT(mOptions.Timing().EndTime().IsNull(),
+               "AutoProfilerTextMarker options shouldn't have an end time");
+    if (profiler_is_active_and_unpaused() &&
+        mOptions.Timing().StartTime().IsNull()) {
+      mOptions.Set(mozilla::MarkerTiming::InstantNow());
+    }
+  }
+
+  ~AutoProfilerTextMarker() {
+    if (profiler_is_active_and_unpaused()) {
+      AUTO_PROFILER_LABEL("TextMarker", PROFILER);
+      mOptions.TimingRef().SetIntervalEnd();
+      AUTO_PROFILER_STATS(AUTO_PROFILER_MARKER_TEXT);
+      profiler_add_marker(
+          mozilla::ProfilerString8View::WrapNullTerminatedString(mMarkerName),
+          mCategory, std::move(mOptions), geckoprofiler::markers::TextMarker{},
+          mText);
+    }
+  }
+
+ protected:
+  const char* mMarkerName;
+  mozilla::MarkerCategory mCategory;
+  mozilla::MarkerOptions mOptions;
+  nsCString mText;
+};
+
+// Creates an AutoProfilerTextMarker RAII object.  This macro is safe to use
+// even if MOZ_GECKO_PROFILER is not #defined.
+#define AUTO_PROFILER_MARKER_TEXT(markerName, categoryName, options, text)  \
+  AutoProfilerTextMarker PROFILER_RAII(                                     \
+      markerName, ::mozilla::baseprofiler::category::categoryName, options, \
+      text)
+
+class MOZ_RAII AutoProfilerTracing {
+ public:
+  AutoProfilerTracing(const char* aCategoryString, const char* aMarkerName,
+                      mozilla::MarkerCategory aCategoryPair,
+                      const mozilla::Maybe<uint64_t>& aInnerWindowID)
+      : mCategoryString(aCategoryString),
+        mMarkerName(aMarkerName),
+        mCategoryPair(aCategoryPair),
+        mInnerWindowID(aInnerWindowID) {
+    profiler_add_marker(
+        mozilla::ProfilerString8View::WrapNullTerminatedString(mMarkerName),
+        mCategoryPair,
+        {mozilla::MarkerTiming::IntervalStart(),
+         mozilla::MarkerInnerWindowId(mInnerWindowID)},
+        geckoprofiler::markers::Tracing{},
+        mozilla::ProfilerString8View::WrapNullTerminatedString(
+            mCategoryString));
+  }
+
+  AutoProfilerTracing(
+      const char* aCategoryString, const char* aMarkerName,
+      mozilla::MarkerCategory aCategoryPair,
+      mozilla::UniquePtr<mozilla::ProfileChunkedBuffer> aBacktrace,
+      const mozilla::Maybe<uint64_t>& aInnerWindowID)
+      : mCategoryString(aCategoryString),
+        mMarkerName(aMarkerName),
+        mCategoryPair(aCategoryPair),
+        mInnerWindowID(aInnerWindowID) {
+    profiler_add_marker(
+        mozilla::ProfilerString8View::WrapNullTerminatedString(mMarkerName),
+        mCategoryPair,
+        {mozilla::MarkerTiming::IntervalStart(),
+         mozilla::MarkerInnerWindowId(mInnerWindowID),
+         mozilla::MarkerStack::TakeBacktrace(std::move(aBacktrace))},
+        geckoprofiler::markers::Tracing{},
+        mozilla::ProfilerString8View::WrapNullTerminatedString(
+            mCategoryString));
+  }
+
+  ~AutoProfilerTracing() {
+    profiler_add_marker(
+        mozilla::ProfilerString8View::WrapNullTerminatedString(mMarkerName),
+        mCategoryPair,
+        {mozilla::MarkerTiming::IntervalEnd(),
+         mozilla::MarkerInnerWindowId(mInnerWindowID)},
+        geckoprofiler::markers::Tracing{},
+        mozilla::ProfilerString8View::WrapNullTerminatedString(
+            mCategoryString));
+  }
+
+ protected:
+  const char* mCategoryString;
+  const char* mMarkerName;
+  const mozilla::MarkerCategory mCategoryPair;
+  const mozilla::Maybe<uint64_t> mInnerWindowID;
+};
+
+// Adds a START/END pair of tracing markers.
+#define AUTO_PROFILER_TRACING_MARKER(categoryString, markerName, categoryPair) \
+  AutoProfilerTracing PROFILER_RAII(categoryString, markerName,                \
+                                    geckoprofiler::category::categoryPair,     \
+                                    mozilla::Nothing())
+#define AUTO_PROFILER_TRACING_MARKER_INNERWINDOWID(                        \
+    categoryString, markerName, categoryPair, innerWindowId)               \
+  AutoProfilerTracing PROFILER_RAII(categoryString, markerName,            \
+                                    geckoprofiler::category::categoryPair, \
+                                    mozilla::Some(innerWindowId))
+#define AUTO_PROFILER_TRACING_MARKER_DOCSHELL(categoryString, markerName, \
+                                              categoryPair, docShell)     \
+  AutoProfilerTracing PROFILER_RAII(                                      \
+      categoryString, markerName, geckoprofiler::category::categoryPair,  \
+      geckoprofiler::markers::detail::                                    \
+          profiler_get_inner_window_id_from_docshell(docShell))
+
+#ifdef MOZ_GECKO_PROFILER
+extern template mozilla::ProfileBufferBlockIndex AddMarkerToBuffer(
+    mozilla::ProfileChunkedBuffer&, const mozilla::ProfilerString8View&,
+    const mozilla::MarkerCategory&, mozilla::MarkerOptions&&,
+    mozilla::baseprofiler::markers::NoPayload);
+
+extern template mozilla::ProfileBufferBlockIndex AddMarkerToBuffer(
+    mozilla::ProfileChunkedBuffer&, const mozilla::ProfilerString8View&,
+    const mozilla::MarkerCategory&, mozilla::MarkerOptions&&,
+    mozilla::baseprofiler::markers::TextMarker, const std::string&);
+
+extern template mozilla::ProfileBufferBlockIndex profiler_add_marker(
+    const mozilla::ProfilerString8View&, const mozilla::MarkerCategory&,
+    mozilla::MarkerOptions&&, mozilla::baseprofiler::markers::TextMarker,
+    const std::string&);
+
+extern template mozilla::ProfileBufferBlockIndex profiler_add_marker(
+    const mozilla::ProfilerString8View&, const mozilla::MarkerCategory&,
+    mozilla::MarkerOptions&&, mozilla::baseprofiler::markers::TextMarker,
+    const nsCString&);
+
+extern template mozilla::ProfileBufferBlockIndex profiler_add_marker(
+    const mozilla::ProfilerString8View&, const mozilla::MarkerCategory&,
+    mozilla::MarkerOptions&&, mozilla::baseprofiler::markers::Tracing,
+    const mozilla::ProfilerString8View&);
+#endif  // MOZ_GECKO_PROFILER
+
+#endif  // ProfilerMarkers_h
diff --git a/tools/profiler/public/ProfilerMarkersDetail.h b/tools/profiler/public/ProfilerMarkersDetail.h
new file mode 100644
index 0000000000..2308a14bb2
--- /dev/null
+++ b/tools/profiler/public/ProfilerMarkersDetail.h
@@ -0,0 +1,31 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerMarkersDetail_h
+#define ProfilerMarkersDetail_h
+
+#ifndef ProfilerMarkers_h
+#  error "This header should only be #included by ProfilerMarkers.h"
+#endif
+
+#include "mozilla/ProfilerMarkersPrerequisites.h"
+
+#ifdef MOZ_GECKO_PROFILER
+
+//                        ~~ HERE BE DRAGONS ~~
+//
+// Everything below is internal implementation detail, you shouldn't need to
+// look at it unless working on the profiler code.
+
+// Header that specializes the (de)serializers for xpcom types.
+#  include "mozilla/ProfileBufferEntrySerializationGeckoExtensions.h"
+
+// Implemented in platform.cpp
+mozilla::ProfileChunkedBuffer& profiler_get_core_buffer();
+
+#endif  // MOZ_GECKO_PROFILER
+
+#endif  // ProfilerMarkersDetail_h
diff --git a/tools/profiler/public/ProfilerMarkersPrerequisites.h b/tools/profiler/public/ProfilerMarkersPrerequisites.h
new file mode 100644
index 0000000000..0f10f7efe2
--- /dev/null
+++ b/tools/profiler/public/ProfilerMarkersPrerequisites.h
@@ -0,0 +1,31 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This header contains basic definitions required to create marker types, and
+// to add markers to the profiler buffers.
+//
+// In most cases, #include "mozilla/ProfilerMarkers.h" instead, or
+// #include "mozilla/ProfilerMarkerTypes.h" for common marker types.
+
+#ifndef ProfilerMarkersPrerequisites_h
+#define ProfilerMarkersPrerequisites_h
+
+#include "mozilla/BaseProfilerMarkersPrerequisites.h"
+#include "mozilla/ProfilerThreadState.h"
+
+#ifdef MOZ_GECKO_PROFILER
+
+namespace geckoprofiler::markers {
+
+// Default marker payload types, with no extra information, not even a marker
+// type and payload. This is intended for label-only markers.
+using NoPayload = ::mozilla::baseprofiler::markers::NoPayload;
+
+}  // namespace geckoprofiler::markers
+
+#endif  // MOZ_GECKO_PROFILER
+
+#endif  // ProfilerMarkersPrerequisites_h
diff --git a/tools/profiler/public/ProfilerParent.h b/tools/profiler/public/ProfilerParent.h
new file mode 100644
index 0000000000..8bd5c71721
--- /dev/null
+++ b/tools/profiler/public/ProfilerParent.h
@@ -0,0 +1,119 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerParent_h
+#define ProfilerParent_h
+
+#include "mozilla/PProfilerParent.h"
+#include "mozilla/RefPtr.h"
+
+class nsIProfilerStartParams;
+
+namespace mozilla {
+
+class ProfileBufferGlobalController;
+class ProfilerParentTracker;
+
+// This is the main process side of the PProfiler protocol.
+// ProfilerParent instances only exist on the main thread of the main process.
+// The other side (ProfilerChild) lives on a background thread in the other
+// process.
+// The creation of PProfiler actors is initiated from the main process, after
+// the other process has been launched.
+// ProfilerParent instances are destroyed once the message channel closes,
+// which can be triggered by either process, depending on which one shuts down
+// first.
+// All ProfilerParent instances are registered with a manager class called
+// ProfilerParentTracker, which has the list of living ProfilerParent instances
+// and handles shutdown.
+class ProfilerParent final : public PProfilerParent {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(ProfilerParent, final)
+
+  static mozilla::ipc::Endpoint<PProfilerChild> CreateForProcess(
+      base::ProcessId aOtherPid);
+
+#ifdef MOZ_GECKO_PROFILER
+  using SingleProcessProfilePromise =
+      MozPromise<IPCProfileAndAdditionalInformation, ResponseRejectReason,
+                 true>;
+
+  struct SingleProcessProfilePromiseAndChildPid {
+    RefPtr<SingleProcessProfilePromise> profilePromise;
+    base::ProcessId childPid;
+  };
+
+  using SingleProcessProgressPromise =
+      MozPromise<GatherProfileProgress, ResponseRejectReason, true>;
+
+  // The following static methods can be called on any thread, but they are
+  // no-ops on anything other than the main thread.
+  // If called on the main thread, the call will be broadcast to all
+  // registered processes (all processes for which we have a ProfilerParent
+  // object).
+  // At the moment, the main process always calls these methods on the main
+  // thread, and that's the only process in which we need to forward these
+  // calls to other processes. The other processes will call these methods on
+  // the ProfilerChild background thread, but those processes don't need to
+  // forward these calls any further.
+
+  // Returns the profiles to expect, as promises and child pids.
+  static nsTArray<SingleProcessProfilePromiseAndChildPid> GatherProfiles();
+
+  // Send a request to get the GatherProfiles() progress update from one child
+  // process, returns a promise to be resolved with that progress.
+  // The promise RefPtr may be null if the child process is unknown.
+  // Progress may be invalid, if the request arrived after the child process
+  // had already responded to the main GatherProfile() IPC, or something went
+  // very wrong in that process.
+  static RefPtr<SingleProcessProgressPromise> RequestGatherProfileProgress(
+      base::ProcessId aChildPid);
+
+  // This will start the profiler in all child processes. The returned promise
+  // will be resolved when all child have completed their operation
+  // (successfully or not.)
+  [[nodiscard]] static RefPtr<GenericPromise> ProfilerStarted(
+      nsIProfilerStartParams* aParams);
+  static void ProfilerWillStopIfStarted();
+  [[nodiscard]] static RefPtr<GenericPromise> ProfilerStopped();
+  [[nodiscard]] static RefPtr<GenericPromise> ProfilerPaused();
+  [[nodiscard]] static RefPtr<GenericPromise> ProfilerResumed();
+  [[nodiscard]] static RefPtr<GenericPromise> ProfilerPausedSampling();
+  [[nodiscard]] static RefPtr<GenericPromise> ProfilerResumedSampling();
+  static void ClearAllPages();
+
+  [[nodiscard]] static RefPtr<GenericPromise> WaitOnePeriodicSampling();
+
+  // Create a "Final" update that the Child can return to its Parent.
+  static ProfileBufferChunkManagerUpdate MakeFinalUpdate();
+
+  // True if the ProfilerParent holds a lock on this thread.
+  static bool IsLockedOnCurrentThread();
+
+ private:
+  friend class ProfileBufferGlobalController;
+  friend class ProfilerParentTracker;
+
+  explicit ProfilerParent(base::ProcessId aChildPid);
+
+  void Init();
+  void ActorDestroy(ActorDestroyReason aActorDestroyReason) override;
+
+  void RequestChunkManagerUpdate();
+
+  base::ProcessId mChildPid;
+  nsTArray<MozPromiseHolder<SingleProcessProfilePromise>>
+      mPendingRequestedProfiles;
+  bool mDestroyed;
+#endif  // MOZ_GECKO_PROFILER
+
+ private:
+  virtual ~ProfilerParent();
+};
+
+}  // namespace mozilla
+
+#endif  // ProfilerParent_h
diff --git a/tools/profiler/public/ProfilerRunnable.h b/tools/profiler/public/ProfilerRunnable.h
new file mode 100644
index 0000000000..b3b4e64043
--- /dev/null
+++ b/tools/profiler/public/ProfilerRunnable.h
@@ -0,0 +1,68 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerRunnable_h
+#define ProfilerRunnable_h
+
+#include "GeckoProfiler.h"
+#include "nsIThreadPool.h"
+
+#if !defined(MOZ_GECKO_PROFILER) || !defined(MOZ_COLLECTING_RUNNABLE_TELEMETRY)
+#  define AUTO_PROFILE_FOLLOWING_RUNNABLE(runnable)
+#else
+#  define AUTO_PROFILE_FOLLOWING_RUNNABLE(runnable)                  \
+    mozilla::Maybe<mozilla::AutoProfileRunnable> raiiRunnableMarker; \
+    if (profiler_thread_is_being_profiled_for_markers()) {           \
+      raiiRunnableMarker.emplace(runnable);                          \
+    }
+
+namespace mozilla {
+
+class MOZ_RAII AutoProfileRunnable {
+ public:
+  explicit AutoProfileRunnable(Runnable* aRunnable)
+      : mStartTime(TimeStamp::Now()) {
+    aRunnable->GetName(mName);
+  }
+  explicit AutoProfileRunnable(nsIRunnable* aRunnable)
+      : mStartTime(TimeStamp::Now()) {
+    nsCOMPtr<nsIThreadPool> threadPool = do_QueryInterface(aRunnable);
+    if (threadPool) {
+      // nsThreadPool::Run has its own call to AUTO_PROFILE_FOLLOWING_RUNNABLE,
+      // avoid nesting runnable markers.
+      return;
+    }
+
+    nsCOMPtr<nsINamed> named = do_QueryInterface(aRunnable);
+    if (named) {
+      named->GetName(mName);
+    }
+  }
+  explicit AutoProfileRunnable(nsACString& aName)
+      : mStartTime(TimeStamp::Now()), mName(aName) {}
+
+  ~AutoProfileRunnable() {
+    if (mName.IsEmpty()) {
+      return;
+    }
+
+    AUTO_PROFILER_LABEL("AutoProfileRunnable", PROFILER);
+    AUTO_PROFILER_STATS(AUTO_PROFILE_RUNNABLE);
+    profiler_add_marker("Runnable", ::mozilla::baseprofiler::category::OTHER,
+                        MarkerTiming::IntervalUntilNowFrom(mStartTime),
+                        geckoprofiler::markers::TextMarker{}, mName);
+  }
+
+ protected:
+  TimeStamp mStartTime;
+  nsAutoCString mName;
+};
+
+}  // namespace mozilla
+
+#endif
+
+#endif  // ProfilerRunnable_h
diff --git a/tools/profiler/public/ProfilerRustBindings.h b/tools/profiler/public/ProfilerRustBindings.h
new file mode 100644
index 0000000000..bf290838a1
--- /dev/null
+++ b/tools/profiler/public/ProfilerRustBindings.h
@@ -0,0 +1,12 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+#ifndef ProfilerRustBindings_h
+#define ProfilerRustBindings_h
+
+#include "mozilla/profiler_ffi_generated.h"
+
+// Add any non-generated support code here
+
+#endif  // ProfilerRustBindings_h
diff --git a/tools/profiler/public/ProfilerState.h b/tools/profiler/public/ProfilerState.h
new file mode 100644
index 0000000000..7a9f3f5c73
--- /dev/null
+++ b/tools/profiler/public/ProfilerState.h
@@ -0,0 +1,399 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This header contains most functions that give information about the Profiler:
+// Whether it is active or not, paused, and the selected features.
+// It is safe to include unconditionally, but uses of structs and functions must
+// be guarded by `#ifdef MOZ_GECKO_PROFILER`.
+
+#ifndef ProfilerState_h
+#define ProfilerState_h
+
+#include <mozilla/DefineEnum.h>
+#include <mozilla/EnumSet.h>
+#include "mozilla/ProfilerUtils.h"
+
+#include <functional>
+
+//---------------------------------------------------------------------------
+// Profiler features
+//---------------------------------------------------------------------------
+
+#if defined(__APPLE__) && defined(__aarch64__)
+#  define POWER_HELP "Sample per process power use"
+#elif defined(__APPLE__) && defined(__x86_64__)
+#  define POWER_HELP \
+    "Record the power used by the entire system with each sample."
+#elif defined(__linux__) && defined(__x86_64__)
+#  define POWER_HELP                                                \
+    "Record the power used by the entire system with each sample. " \
+    "Only available with Intel CPUs and requires setting "          \
+    "the sysctl kernel.perf_event_paranoid to 0."
+
+#elif defined(_MSC_VER)
+#  define POWER_HELP                                                       \
+    "Record the value of every energy meter available on the system with " \
+    "each sample. Only available on Windows 11 with Intel CPUs."
+#else
+#  define POWER_HELP "Not supported on this platform."
+#endif
+
+// Higher-order macro containing all the feature info in one place. Define
+// |MACRO| appropriately to extract the relevant parts. Note that the number
+// values are used internally only and so can be changed without consequence.
+// Any changes to this list should also be applied to the feature list in
+// toolkit/components/extensions/schemas/geckoProfiler.json.
+// *** Synchronize with lists in BaseProfilerState.h and geckoProfiler.json ***
+#define PROFILER_FOR_EACH_FEATURE(MACRO)                                   \
+  MACRO(0, "java", Java, "Profile Java code, Android only")                \
+                                                                           \
+  MACRO(1, "js", JS,                                                       \
+        "Get the JS engine to expose the JS stack to the profiler")        \
+                                                                           \
+  MACRO(2, "mainthreadio", MainThreadIO, "Add main thread file I/O")       \
+                                                                           \
+  MACRO(3, "fileio", FileIO,                                               \
+        "Add file I/O from all profiled threads, implies mainthreadio")    \
+                                                                           \
+  MACRO(4, "fileioall", FileIOAll,                                         \
+        "Add file I/O from all threads, implies fileio")                   \
+                                                                           \
+  MACRO(5, "nomarkerstacks", NoMarkerStacks,                               \
+        "Markers do not capture stacks, to reduce overhead")               \
+                                                                           \
+  MACRO(6, "screenshots", Screenshots,                                     \
+        "Take a snapshot of the window on every composition")              \
+                                                                           \
+  MACRO(7, "seqstyle", SequentialStyle,                                    \
+        "Disable parallel traversal in styling")                           \
+                                                                           \
+  MACRO(8, "stackwalk", StackWalk,                                         \
+        "Walk the C++ stack, not available on all platforms")              \
+                                                                           \
+  MACRO(9, "jsallocations", JSAllocations,                                 \
+        "Have the JavaScript engine track allocations")                    \
+                                                                           \
+  MACRO(10, "nostacksampling", NoStackSampling,                            \
+        "Disable all stack sampling: Cancels \"js\", \"stackwalk\" and "   \
+        "labels")                                                          \
+                                                                           \
+  MACRO(11, "nativeallocations", NativeAllocations,                        \
+        "Collect the stacks from a smaller subset of all native "          \
+        "allocations, biasing towards collecting larger allocations")      \
+                                                                           \
+  MACRO(12, "ipcmessages", IPCMessages,                                    \
+        "Have the IPC layer track cross-process messages")                 \
+                                                                           \
+  MACRO(13, "audiocallbacktracing", AudioCallbackTracing,                  \
+        "Audio callback tracing")                                          \
+                                                                           \
+  MACRO(14, "cpu", CPUUtilization, "CPU utilization")                      \
+                                                                           \
+  MACRO(15, "notimerresolutionchange", NoTimerResolutionChange,            \
+        "Do not adjust the timer resolution for sampling, so that other "  \
+        "Firefox timers do not get affected")                              \
+                                                                           \
+  MACRO(16, "cpuallthreads", CPUAllThreads,                                \
+        "Sample the CPU utilization of all registered threads")            \
+                                                                           \
+  MACRO(17, "samplingallthreads", SamplingAllThreads,                      \
+        "Sample the stacks of all registered threads")                     \
+                                                                           \
+  MACRO(18, "markersallthreads", MarkersAllThreads,                        \
+        "Record markers from all registered threads")                      \
+                                                                           \
+  MACRO(19, "unregisteredthreads", UnregisteredThreads,                    \
+        "Discover and profile unregistered threads -- beware: expensive!") \
+                                                                           \
+  MACRO(20, "processcpu", ProcessCPU,                                      \
+        "Sample the CPU utilization of each process")                      \
+                                                                           \
+  MACRO(21, "power", Power, POWER_HELP)
+// *** Synchronize with lists in BaseProfilerState.h and geckoProfiler.json ***
+
+struct ProfilerFeature {
+#define DECLARE(n_, str_, Name_, desc_)                                \
+  static constexpr uint32_t Name_ = (1u << n_);                        \
+  [[nodiscard]] static constexpr bool Has##Name_(uint32_t aFeatures) { \
+    return aFeatures & Name_;                                          \
+  }                                                                    \
+  static constexpr void Set##Name_(uint32_t& aFeatures) {              \
+    aFeatures |= Name_;                                                \
+  }                                                                    \
+  static constexpr void Clear##Name_(uint32_t& aFeatures) {            \
+    aFeatures &= ~Name_;                                               \
+  }
+
+  // Define a bitfield constant, a getter, and two setters for each feature.
+  PROFILER_FOR_EACH_FEATURE(DECLARE)
+
+#undef DECLARE
+};
+
+// clang-format off
+MOZ_DEFINE_ENUM_CLASS(ProfilingState,(
+  // A callback will be invoked ...
+  AlreadyActive,     // if the profiler is active when the callback is added.
+  RemovingCallback,  // when the callback is removed.
+  Started,           // after the profiler has started.
+  Pausing,           // before the profiler is paused.
+  Resumed,           // after the profiler has resumed.
+  GeneratingProfile, // before a profile is created.
+  Stopping,          // before the profiler stops (unless restarting afterward).
+  ShuttingDown       // before the profiler is shut down.
+));
+// clang-format on
+
+[[nodiscard]] inline static const char* ProfilingStateToString(
+    ProfilingState aProfilingState) {
+  switch (aProfilingState) {
+    case ProfilingState::AlreadyActive:
+      return "Profiler already active";
+    case ProfilingState::RemovingCallback:
+      return "Callback being removed";
+    case ProfilingState::Started:
+      return "Profiler started";
+    case ProfilingState::Pausing:
+      return "Profiler pausing";
+    case ProfilingState::Resumed:
+      return "Profiler resumed";
+    case ProfilingState::GeneratingProfile:
+      return "Generating profile";
+    case ProfilingState::Stopping:
+      return "Profiler stopping";
+    case ProfilingState::ShuttingDown:
+      return "Profiler shutting down";
+    default:
+      MOZ_ASSERT_UNREACHABLE("Unexpected ProfilingState enum value");
+      return "?";
+  }
+}
+
+using ProfilingStateSet = mozilla::EnumSet<ProfilingState>;
+
+[[nodiscard]] constexpr ProfilingStateSet AllProfilingStates() {
+  ProfilingStateSet set;
+  using Value = std::underlying_type_t<ProfilingState>;
+  for (Value stateValue = 0;
+       stateValue <= static_cast<Value>(kHighestProfilingState); ++stateValue) {
+    set += static_cast<ProfilingState>(stateValue);
+  }
+  return set;
+}
+
+// Type of callbacks to be invoked at certain state changes.
+// It must NOT call profiler_add/remove_state_change_callback().
+using ProfilingStateChangeCallback = std::function<void(ProfilingState)>;
+
+#ifndef MOZ_GECKO_PROFILER
+
+[[nodiscard]] inline bool profiler_is_active() { return false; }
+[[nodiscard]] inline bool profiler_is_active_and_unpaused() { return false; }
+[[nodiscard]] inline bool profiler_feature_active(uint32_t aFeature) {
+  return false;
+}
+[[nodiscard]] inline bool profiler_is_locked_on_current_thread() {
+  return false;
+}
+inline void profiler_add_state_change_callback(
+    ProfilingStateSet aProfilingStateSet,
+    ProfilingStateChangeCallback&& aCallback, uintptr_t aUniqueIdentifier = 0) {
+}
+inline void profiler_remove_state_change_callback(uintptr_t aUniqueIdentifier) {
+}
+
+#else  // !MOZ_GECKO_PROFILER
+
+#  include "mozilla/Atomics.h"
+#  include "mozilla/Maybe.h"
+
+#  include <stdint.h>
+
+namespace mozilla::profiler::detail {
+
+// RacyFeatures is only defined in this header file so that its methods can
+// be inlined into profiler_is_active(). Please do not use anything from the
+// detail namespace outside the profiler.
+
+// Within the profiler's code, the preferred way to check profiler activeness
+// and features is via ActivePS(). However, that requires locking gPSMutex.
+// There are some hot operations where absolute precision isn't required, so we
+// duplicate the activeness/feature state in a lock-free manner in this class.
+class RacyFeatures {
+ public:
+  static void SetActive(uint32_t aFeatures) {
+    sActiveAndFeatures = Active | aFeatures;
+  }
+
+  static void SetInactive() { sActiveAndFeatures = 0; }
+
+  static void SetPaused() { sActiveAndFeatures |= Paused; }
+
+  static void SetUnpaused() { sActiveAndFeatures &= ~Paused; }
+
+  static void SetSamplingPaused() { sActiveAndFeatures |= SamplingPaused; }
+
+  static void SetSamplingUnpaused() { sActiveAndFeatures &= ~SamplingPaused; }
+
+  [[nodiscard]] static mozilla::Maybe<uint32_t> FeaturesIfActive() {
+    if (uint32_t af = sActiveAndFeatures; af & Active) {
+      // Active, remove the Active&Paused bits to get all features.
+      return Some(af & ~(Active | Paused | SamplingPaused));
+    }
+    return Nothing();
+  }
+
+  [[nodiscard]] static mozilla::Maybe<uint32_t> FeaturesIfActiveAndUnpaused() {
+    if (uint32_t af = sActiveAndFeatures; (af & (Active | Paused)) == Active) {
+      // Active but not fully paused, remove the Active and sampling-paused bits
+      // to get all features.
+      return Some(af & ~(Active | SamplingPaused));
+    }
+    return Nothing();
+  }
+
+  // This implementation must be kept in sync with `gecko_profiler::is_active`
+  // in the Profiler Rust API.
+  [[nodiscard]] static bool IsActive() {
+    return uint32_t(sActiveAndFeatures) & Active;
+  }
+
+  [[nodiscard]] static bool IsActiveWithFeature(uint32_t aFeature) {
+    uint32_t af = sActiveAndFeatures;  // copy it first
+    return (af & Active) && (af & aFeature);
+  }
+
+  [[nodiscard]] static bool IsActiveWithoutFeature(uint32_t aFeature) {
+    uint32_t af = sActiveAndFeatures;  // copy it first
+    return (af & Active) && !(af & aFeature);
+  }
+
+  // True if profiler is active, and not fully paused.
+  // Note that periodic sampling *could* be paused!
+  // This implementation must be kept in sync with
+  // `gecko_profiler::can_accept_markers` in the Profiler Rust API.
+  [[nodiscard]] static bool IsActiveAndUnpaused() {
+    uint32_t af = sActiveAndFeatures;  // copy it first
+    return (af & Active) && !(af & Paused);
+  }
+
+  // True if profiler is active, and sampling is not paused (though generic
+  // `SetPaused()` or specific `SetSamplingPaused()`).
+  [[nodiscard]] static bool IsActiveAndSamplingUnpaused() {
+    uint32_t af = sActiveAndFeatures;  // copy it first
+    return (af & Active) && !(af & (Paused | SamplingPaused));
+  }
+
+ private:
+  static constexpr uint32_t Active = 1u << 31;
+  static constexpr uint32_t Paused = 1u << 30;
+  static constexpr uint32_t SamplingPaused = 1u << 29;
+
+// Ensure Active/Paused don't overlap with any of the feature bits.
+#  define NO_OVERLAP(n_, str_, Name_, desc_)                \
+    static_assert(ProfilerFeature::Name_ != SamplingPaused, \
+                  "bad feature value");
+
+  PROFILER_FOR_EACH_FEATURE(NO_OVERLAP);
+
+#  undef NO_OVERLAP
+
+  // We combine the active bit with the feature bits so they can be read or
+  // written in a single atomic operation. Accesses to this atomic are not
+  // recorded by web replay as they may occur at non-deterministic points.
+  static mozilla::Atomic<uint32_t, mozilla::MemoryOrdering::Relaxed>
+      sActiveAndFeatures;
+};
+
+}  // namespace mozilla::profiler::detail
+
+//---------------------------------------------------------------------------
+// Get information from the profiler
+//---------------------------------------------------------------------------
+
+// Is the profiler active? Note: the return value of this function can become
+// immediately out-of-date. E.g. the profile might be active but then
+// profiler_stop() is called immediately afterward. One common and reasonable
+// pattern of usage is the following:
+//
+//   if (profiler_is_active()) {
+//     ExpensiveData expensiveData = CreateExpensiveData();
+//     PROFILER_OPERATION(expensiveData);
+//   }
+//
+// where PROFILER_OPERATION is a no-op if the profiler is inactive. In this
+// case the profiler_is_active() check is just an optimization -- it prevents
+// us calling CreateExpensiveData() unnecessarily in most cases, but the
+// expensive data will end up being created but not used if another thread
+// stops the profiler between the CreateExpensiveData() and PROFILER_OPERATION
+// calls.
+[[nodiscard]] inline bool profiler_is_active() {
+  return mozilla::profiler::detail::RacyFeatures::IsActive();
+}
+
+// Same as profiler_is_active(), but also checks if the profiler is not paused.
+[[nodiscard]] inline bool profiler_is_active_and_unpaused() {
+  return mozilla::profiler::detail::RacyFeatures::IsActiveAndUnpaused();
+}
+
+// Is the profiler active and paused? Returns false if the profiler is inactive.
+[[nodiscard]] bool profiler_is_paused();
+
+// Is the profiler active and sampling is paused? Returns false if the profiler
+// is inactive.
+[[nodiscard]] bool profiler_is_sampling_paused();
+
+// Get all the features supported by the profiler that are accepted by
+// profiler_start(). The result is the same whether the profiler is active or
+// not.
+[[nodiscard]] uint32_t profiler_get_available_features();
+
+// Returns the full feature set if the profiler is active.
+// Note: the return value can become immediately out-of-date, much like the
+// return value of profiler_is_active().
+[[nodiscard]] inline mozilla::Maybe<uint32_t> profiler_features_if_active() {
+  return mozilla::profiler::detail::RacyFeatures::FeaturesIfActive();
+}
+
+// Returns the full feature set if the profiler is active and unpaused.
+// Note: the return value can become immediately out-of-date, much like the
+// return value of profiler_is_active().
+[[nodiscard]] inline mozilla::Maybe<uint32_t>
+profiler_features_if_active_and_unpaused() {
+  return mozilla::profiler::detail::RacyFeatures::FeaturesIfActiveAndUnpaused();
+}
+
+// Check if a profiler feature (specified via the ProfilerFeature type) is
+// active. Returns false if the profiler is inactive. Note: the return value
+// can become immediately out-of-date, much like the return value of
+// profiler_is_active().
+[[nodiscard]] bool profiler_feature_active(uint32_t aFeature);
+
+// Check if the profiler is active without a feature (specified via the
+// ProfilerFeature type). Note: the return value can become immediately
+// out-of-date, much like the return value of profiler_is_active().
+[[nodiscard]] bool profiler_active_without_feature(uint32_t aFeature);
+
+// Returns true if any of the profiler mutexes are currently locked *on the
+// current thread*. This may be used by re-entrant code that may call profiler
+// functions while the same of a different profiler mutex is locked, which could
+// deadlock.
+[[nodiscard]] bool profiler_is_locked_on_current_thread();
+
+// Install a callback to be invoked at any of the given profiling state changes.
+// An optional non-zero identifier may be given, to allow later removal of the
+// callback, the caller is responsible for making sure it's really unique (e.g.,
+// by using a pointer to an object it owns.)
+void profiler_add_state_change_callback(
+    ProfilingStateSet aProfilingStateSet,
+    ProfilingStateChangeCallback&& aCallback, uintptr_t aUniqueIdentifier = 0);
+
+// Remove the callback with the given non-zero identifier.
+void profiler_remove_state_change_callback(uintptr_t aUniqueIdentifier);
+
+#endif  // MOZ_GECKO_PROFILER
+
+#endif  // ProfilerState_h
diff --git a/tools/profiler/public/ProfilerThreadPlatformData.h b/tools/profiler/public/ProfilerThreadPlatformData.h
new file mode 100644
index 0000000000..c243a8ee02
--- /dev/null
+++ b/tools/profiler/public/ProfilerThreadPlatformData.h
@@ -0,0 +1,80 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerThreadPlatformData_h
+#define ProfilerThreadPlatformData_h
+
+#include "mozilla/ProfilerUtils.h"
+
+#if defined(__APPLE__)
+#  include <mach/mach_types.h>
+#elif defined(__linux__) || defined(__ANDROID__) || defined(__FreeBSD__)
+#  include "mozilla/Maybe.h"
+#  include <time.h>
+#endif
+
+namespace mozilla::profiler {
+
+class PlatformData {
+#if (defined(_MSC_VER) || defined(__MINGW32__)) && defined(MOZ_GECKO_PROFILER)
+ public:
+  explicit PlatformData(ProfilerThreadId aThreadId);
+  ~PlatformData();
+
+  // Faking win32's HANDLE, because #including "windows.h" here causes trouble
+  // (e.g., it #defines `Yield` as nothing!)
+  // This type is static_check'ed against HANDLE in platform-win32.cpp.
+  using WindowsHandle = void*;
+  WindowsHandle ProfiledThread() const { return mProfiledThread; }
+
+ private:
+  WindowsHandle mProfiledThread;
+#elif defined(__APPLE__) && defined(MOZ_GECKO_PROFILER)
+ public:
+  explicit PlatformData(ProfilerThreadId aThreadId);
+  ~PlatformData();
+  thread_act_t ProfiledThread() const { return mProfiledThread; }
+
+ private:
+  // Note: for mProfiledThread Mach primitives are used instead of pthread's
+  // because the latter doesn't provide thread manipulation primitives
+  // required. For details, consult "Mac OS X Internals" book, Section 7.3.
+  thread_act_t mProfiledThread;
+#elif (defined(__linux__) || defined(__ANDROID__) || defined(__FreeBSD__)) && \
+    defined(MOZ_GECKO_PROFILER)
+ public:
+  explicit PlatformData(ProfilerThreadId aThreadId);
+  ~PlatformData();
+  // Clock Id for this profiled thread. `Nothing` if `pthread_getcpuclockid`
+  // failed (e.g., if the system doesn't support per-thread clocks).
+  Maybe<clockid_t> GetClockId() const { return mClockId; }
+
+ private:
+  Maybe<clockid_t> mClockId;
+#else
+ public:
+  explicit PlatformData(ProfilerThreadId aThreadId) {}
+#endif
+};
+
+/**
+ * Return the number of nanoseconds of CPU time used since thread start.
+ *
+ * @return true on success.
+ */
+#if defined(MOZ_GECKO_PROFILER)
+bool GetCpuTimeSinceThreadStartInNs(uint64_t* aResult,
+                                    const PlatformData& aPlatformData);
+#else
+static inline bool GetCpuTimeSinceThreadStartInNs(
+    uint64_t* aResult, const PlatformData& aPlatformData) {
+  return false;
+}
+#endif
+
+}  // namespace mozilla::profiler
+
+#endif  // ProfilerThreadPlatformData_h
diff --git a/tools/profiler/public/ProfilerThreadRegistration.h b/tools/profiler/public/ProfilerThreadRegistration.h
new file mode 100644
index 0000000000..3fb931987d
--- /dev/null
+++ b/tools/profiler/public/ProfilerThreadRegistration.h
@@ -0,0 +1,367 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerThreadRegistration_h
+#define ProfilerThreadRegistration_h
+
+#include "mozilla/BaseProfilerDetail.h"
+#include "mozilla/ProfilerThreadRegistrationData.h"
+#include "mozilla/ThreadLocal.h"
+
+namespace mozilla::profiler {
+
+class ThreadRegistry;
+
+// To use as RAII object, or through RegisterThread/UnregisterThread.
+// Automatically registers itself with TLS and Profiler.
+// It can be safely nested, but nested instances are just ignored.
+// See Get.../With... functions for how to access the data.
+class ThreadRegistration {
+ private:
+  using DataMutex = baseprofiler::detail::BaseProfilerMutex;
+  using DataLock = baseprofiler::detail::BaseProfilerAutoLock;
+
+ public:
+  // Constructor to use as RAII auto-registration object.
+  // It stores itself in the TLS (its effective owner), and gives its pointer to
+  // the Profiler.
+  ThreadRegistration(const char* aName, const void* aStackTop);
+
+  // Destruction reverses construction: Remove pointer from the Profiler (except
+  // for the main thread, because it should be done by the profiler itself) and
+  // from the TLS.
+  ~ThreadRegistration();
+
+  // Manual construction&destruction, if RAII is not possible or too expensive
+  // in stack space.
+  // RegisterThread() *must* be paired with exactly one UnregisterThread() on
+  // the same thread. (Extra UnregisterThread() calls are handled safely, but
+  // they may cause profiling of this thread to stop earlier than expected.)
+  static ProfilingStack* RegisterThread(const char* aName,
+                                        const void* aStackTop);
+  static void UnregisterThread();
+
+  [[nodiscard]] static bool IsRegistered() { return GetFromTLS(); }
+
+  // Prevent copies&moves.
+  ThreadRegistration(const ThreadRegistration&) = delete;
+  ThreadRegistration& operator=(const ThreadRegistration&) = delete;
+
+  // Aliases to data accessors (removing the ThreadRegistration prefix).
+
+  using UnlockedConstReader = ThreadRegistrationUnlockedConstReader;
+  using UnlockedConstReaderAndAtomicRW =
+      ThreadRegistrationUnlockedConstReaderAndAtomicRW;
+  using UnlockedRWForLockedProfiler =
+      ThreadRegistrationUnlockedRWForLockedProfiler;
+  using UnlockedReaderAndAtomicRWOnThread =
+      ThreadRegistrationUnlockedReaderAndAtomicRWOnThread;
+  using LockedRWFromAnyThread = ThreadRegistrationLockedRWFromAnyThread;
+  using LockedRWOnThread = ThreadRegistrationLockedRWOnThread;
+
+  // On-thread access from the TLS, providing the following data accessors:
+  // UnlockedConstReader, UnlockedConstReaderAndAtomicRW,
+  // UnlockedRWForLockedProfiler, UnlockedReaderAndAtomicRWOnThread, and
+  // LockedRWOnThread.
+  // (See ThreadRegistry class for OFF-thread access.)
+
+  // Reference-like class pointing at the ThreadRegistration for the current
+  // thread.
+  class OnThreadRef {
+   public:
+    // const UnlockedConstReader
+
+    [[nodiscard]] const UnlockedConstReader& UnlockedConstReaderCRef() const {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedConstReader(F&& aF) const {
+      return std::forward<F>(aF)(UnlockedConstReaderCRef());
+    }
+
+    // const UnlockedConstReaderAndAtomicRW
+
+    [[nodiscard]] const UnlockedConstReaderAndAtomicRW&
+    UnlockedConstReaderAndAtomicRWCRef() const {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedConstReaderAndAtomicRW(F&& aF) const {
+      return std::forward<F>(aF)(UnlockedConstReaderAndAtomicRWCRef());
+    }
+
+    // UnlockedConstReaderAndAtomicRW
+
+    [[nodiscard]] UnlockedConstReaderAndAtomicRW&
+    UnlockedConstReaderAndAtomicRWRef() {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedConstReaderAndAtomicRW(F&& aF) {
+      return std::forward<F>(aF)(UnlockedConstReaderAndAtomicRWRef());
+    }
+
+    // const UnlockedRWForLockedProfiler
+
+    [[nodiscard]] const UnlockedRWForLockedProfiler&
+    UnlockedRWForLockedProfilerCRef() const {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedRWForLockedProfiler(F&& aF) const {
+      return std::forward<F>(aF)(UnlockedRWForLockedProfilerCRef());
+    }
+
+    // UnlockedRWForLockedProfiler
+
+    [[nodiscard]] UnlockedRWForLockedProfiler&
+    UnlockedRWForLockedProfilerRef() {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedRWForLockedProfiler(F&& aF) {
+      return std::forward<F>(aF)(UnlockedRWForLockedProfilerRef());
+    }
+
+    // const UnlockedReaderAndAtomicRWOnThread
+
+    [[nodiscard]] const UnlockedReaderAndAtomicRWOnThread&
+    UnlockedReaderAndAtomicRWOnThreadCRef() const {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedReaderAndAtomicRWOnThread(F&& aF) const {
+      return std::forward<F>(aF)(UnlockedReaderAndAtomicRWOnThreadCRef());
+    }
+
+    // UnlockedReaderAndAtomicRWOnThread
+
+    [[nodiscard]] UnlockedReaderAndAtomicRWOnThread&
+    UnlockedReaderAndAtomicRWOnThreadRef() {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedReaderAndAtomicRWOnThread(F&& aF) {
+      return std::forward<F>(aF)(UnlockedReaderAndAtomicRWOnThreadRef());
+    }
+
+    // const LockedRWOnThread through ConstRWOnThreadWithLock
+
+    // Locking order: Profiler, ThreadRegistry, ThreadRegistration.
+    class ConstRWOnThreadWithLock {
+     public:
+      [[nodiscard]] const LockedRWOnThread& DataCRef() const {
+        return mLockedRWOnThread;
+      }
+      [[nodiscard]] const LockedRWOnThread* operator->() const {
+        return &mLockedRWOnThread;
+      }
+
+     private:
+      friend class OnThreadRef;
+      ConstRWOnThreadWithLock(const LockedRWOnThread& aLockedRWOnThread,
+                              DataMutex& aDataMutex)
+          : mLockedRWOnThread(aLockedRWOnThread), mDataLock(aDataMutex) {}
+
+      const LockedRWOnThread& mLockedRWOnThread;
+      DataLock mDataLock;
+    };
+
+    [[nodiscard]] ConstRWOnThreadWithLock ConstLockedRWOnThread() const {
+      return ConstRWOnThreadWithLock{mThreadRegistration->mData,
+                                     mThreadRegistration->mDataMutex};
+    }
+
+    template <typename F>
+    auto WithConstLockedRWOnThread(F&& aF) const {
+      ConstRWOnThreadWithLock lockedData = ConstLockedRWOnThread();
+      return std::forward<F>(aF)(lockedData.DataCRef());
+    }
+
+    // LockedRWOnThread through RWOnThreadWithLock
+
+    // Locking order: Profiler, ThreadRegistry, ThreadRegistration.
+    class RWOnThreadWithLock {
+     public:
+      [[nodiscard]] const LockedRWOnThread& DataCRef() const {
+        return mLockedRWOnThread;
+      }
+      [[nodiscard]] LockedRWOnThread& DataRef() { return mLockedRWOnThread; }
+      [[nodiscard]] const LockedRWOnThread* operator->() const {
+        return &mLockedRWOnThread;
+      }
+      [[nodiscard]] LockedRWOnThread* operator->() {
+        return &mLockedRWOnThread;
+      }
+
+     private:
+      friend class OnThreadRef;
+      RWOnThreadWithLock(LockedRWOnThread& aLockedRWOnThread,
+                         DataMutex& aDataMutex)
+          : mLockedRWOnThread(aLockedRWOnThread), mDataLock(aDataMutex) {}
+
+      LockedRWOnThread& mLockedRWOnThread;
+      DataLock mDataLock;
+    };
+
+    [[nodiscard]] RWOnThreadWithLock GetLockedRWOnThread() {
+      return RWOnThreadWithLock{mThreadRegistration->mData,
+                                mThreadRegistration->mDataMutex};
+    }
+
+    template <typename F>
+    auto WithLockedRWOnThread(F&& aF) {
+      RWOnThreadWithLock lockedData = GetLockedRWOnThread();
+      return std::forward<F>(aF)(lockedData.DataRef());
+    }
+
+    // This is needed to allow OnThreadPtr::operator-> to return a temporary
+    // OnThreadRef object, for which `->` must work; Here it provides a pointer
+    // to itself, so that the next follow-up `->` will work as member accessor.
+    OnThreadRef* operator->() && { return this; }
+
+   private:
+    // Only ThreadRegistration should construct an OnThreadRef.
+    friend class ThreadRegistration;
+    explicit OnThreadRef(ThreadRegistration& aThreadRegistration)
+        : mThreadRegistration(&aThreadRegistration) {}
+
+    // Allow ThreadRegistry to read mThreadRegistration.
+    friend class ThreadRegistry;
+
+    // Guaranted to be non-null by construction from a reference.
+    ThreadRegistration* mThreadRegistration;
+  };
+
+  // Pointer-like class pointing at the ThreadRegistration for the current
+  // thread, if one was registered.
+  class OnThreadPtr {
+   public:
+    [[nodiscard]] explicit operator bool() const { return mThreadRegistration; }
+
+    // Note that this resolves to a temporary OnThreadRef object, which has all
+    // the allowed data accessors.
+    [[nodiscard]] OnThreadRef operator*() const {
+      MOZ_ASSERT(mThreadRegistration);
+      return OnThreadRef(*mThreadRegistration);
+    }
+
+    // Note that this resolves to a temporary OnThreadRef object, which also
+    // overloads operator-> and has all the allowed data accessors.
+    [[nodiscard]] OnThreadRef operator->() const {
+      MOZ_ASSERT(mThreadRegistration);
+      return OnThreadRef(*mThreadRegistration);
+    }
+
+   private:
+    friend class ThreadRegistration;
+    explicit OnThreadPtr(ThreadRegistration* aThreadRegistration)
+        : mThreadRegistration(aThreadRegistration) {}
+
+    ThreadRegistration* mThreadRegistration;
+  };
+
+  [[nodiscard]] static OnThreadPtr GetOnThreadPtr() {
+    return OnThreadPtr{GetFromTLS()};
+  }
+
+  // Call `F(OnThreadRef)`.
+  template <typename F>
+  static void WithOnThreadRef(F&& aF) {
+    const auto* tls = GetTLS();
+    if (tls) {
+      ThreadRegistration* tr = tls->get();
+      if (tr) {
+        std::forward<F>(aF)(OnThreadRef{*tr});
+      }
+    }
+  }
+
+  // Call `F(OnThreadRef)`.
+  template <typename F, typename FallbackReturn>
+  [[nodiscard]] static auto WithOnThreadRefOr(F&& aF,
+                                              FallbackReturn&& aFallbackReturn)
+      -> decltype(std::forward<F>(aF)(std::declval<OnThreadRef>())) {
+    const auto* tls = GetTLS();
+    if (tls) {
+      ThreadRegistration* tr = tls->get();
+      if (tr) {
+        return std::forward<F>(aF)(OnThreadRef{*tr});
+      }
+    }
+    return std::forward<FallbackReturn>(aFallbackReturn);
+  }
+
+  [[nodiscard]] static bool IsDataMutexLockedOnCurrentThread() {
+    if (const ThreadRegistration* tr = GetFromTLS(); tr) {
+      return tr->mDataMutex.IsLockedOnCurrentThread();
+    }
+    return false;
+  }
+
+  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
+    DataLock lock(mDataMutex);
+    return mData.SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
+    // aMallocSizeOf can only be used on head-allocated objects. Stack
+    // allocations and static objects are not counted.
+    return (mIsOnHeap ? aMallocSizeOf(this) : 0) +
+           SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+ private:
+  friend class ThreadRegistry;
+
+  // This is what is embedded inside ThreadRegistration.
+  // References to sub-classes will be provided, to limit access as appropriate.
+  class EmbeddedData final : public LockedRWOnThread {
+   private:
+    // Only ThreadRegistration can construct (its embedded) `mData`.
+    friend class ThreadRegistration;
+    EmbeddedData(const char* aName, const void* aStackTop)
+        : LockedRWOnThread(aName, aStackTop) {}
+  };
+  EmbeddedData mData;
+
+  // Used when writing on self thread, and for any access from any thread.
+  // Locking order: Profiler, ThreadRegistry, ThreadRegistration.
+  mutable DataMutex mDataMutex;
+
+  // In case of nested (non-RAII) registrations. Only accessed on thread.
+  int mOtherRegistrations = 0;
+
+  // Set to true if allocated by `RegisterThread()`. Otherwise we assume that it
+  // is on the stack.
+  bool mIsOnHeap = false;
+
+  // Only accessed by ThreadRegistry on this thread.
+  bool mIsRegistryLockedSharedOnThisThread = false;
+
+  static MOZ_THREAD_LOCAL(ThreadRegistration*) tlsThreadRegistration;
+
+  [[nodiscard]] static decltype(tlsThreadRegistration)* GetTLS() {
+    static const bool initialized = tlsThreadRegistration.init();
+    return initialized ? &tlsThreadRegistration : nullptr;
+  }
+
+  [[nodiscard]] static ThreadRegistration* GetFromTLS() {
+    const auto tls = GetTLS();
+    return tls ? tls->get() : nullptr;
+  }
+};
+
+}  // namespace mozilla::profiler
+
+#endif  // ProfilerThreadRegistration_h
diff --git a/tools/profiler/public/ProfilerThreadRegistrationData.h b/tools/profiler/public/ProfilerThreadRegistrationData.h
new file mode 100644
index 0000000000..7c14290e4c
--- /dev/null
+++ b/tools/profiler/public/ProfilerThreadRegistrationData.h
@@ -0,0 +1,537 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This header contains classes that hold data related to thread profiling:
+// Data members are stored `protected` in `ThreadRegistrationData`.
+// Non-virtual sub-classes of ProfilerThreadRegistrationData provide layers of
+// public accessors to subsets of the data. Each level builds on the previous
+// one and adds further access to more data, but always with the appropriate
+// guards where necessary.
+// These classes have protected constructors, so only some trusted classes
+// `ThreadRegistration` and `ThreadRegistry` will be able to construct them, and
+// then give limited access depending on who asks (the owning thread or another
+// one), and how much data they actually need.
+//
+// The hierarchy is, from base to most derived:
+// - ThreadRegistrationData
+// - ThreadRegistrationUnlockedConstReader
+// - ThreadRegistrationUnlockedConstReaderAndAtomicRW
+// - ThreadRegistrationUnlockedRWForLockedProfiler
+// - ThreadRegistrationUnlockedReaderAndAtomicRWOnThread
+// - ThreadRegistrationLockedRWFromAnyThread
+// - ThreadRegistrationLockedRWOnThread
+// - ThreadRegistration::EmbeddedData (actual data member in ThreadRegistration)
+//
+// Tech detail: These classes need to be a single hierarchy so that
+// `ThreadRegistration` can contain the most-derived class, and from there can
+// publish references to base classes without relying on Undefined Behavior.
+// (It's not allowed to have some object and give a reference to a sub-class,
+// unless that object was *really* constructed as that sub-class at least, even
+// if that sub-class only adds member functions!)
+// And where appropriate, these references will come along with the required
+// lock.
+
+#ifndef ProfilerThreadRegistrationData_h
+#define ProfilerThreadRegistrationData_h
+
+#include "js/ProfilingFrameIterator.h"
+#include "js/ProfilingStack.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/BaseProfilerDetail.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/ProfilerThreadPlatformData.h"
+#include "mozilla/ProfilerThreadRegistrationInfo.h"
+#include "nsCOMPtr.h"
+#include "nsIThread.h"
+
+class ProfiledThreadData;
+class PSAutoLock;
+struct JSContext;
+
+// Enum listing which profiling features are active for a single thread.
+enum class ThreadProfilingFeatures : uint32_t {
+  // The thread is not being profiled at all (either the profiler is not
+  // running, or this thread is not examined during profiling.)
+  NotProfiled = 0u,
+
+  // Single features, binary exclusive. May be `Combine()`d.
+  CPUUtilization = 1u << 0,
+  Sampling = 1u << 1,
+  Markers = 1u << 2,
+
+  // All possible features. Usually used as a mask to see if any feature is
+  // active at a given time.
+  Any = CPUUtilization | Sampling | Markers
+};
+
+// Binary OR of one of more ThreadProfilingFeatures, to mix all arguments.
+template <typename... Ts>
+[[nodiscard]] constexpr ThreadProfilingFeatures Combine(
+    ThreadProfilingFeatures a1, Ts... as) {
+  static_assert((true && ... &&
+                 std::is_same_v<std::remove_cv_t<std::remove_reference_t<Ts>>,
+                                ThreadProfilingFeatures>));
+  return static_cast<ThreadProfilingFeatures>(
+      (static_cast<std::underlying_type_t<ThreadProfilingFeatures>>(a1) | ... |
+       static_cast<std::underlying_type_t<ThreadProfilingFeatures>>(as)));
+}
+
+// Binary AND of one of more ThreadProfilingFeatures, to find features common to
+// all arguments.
+template <typename... Ts>
+[[nodiscard]] constexpr ThreadProfilingFeatures Intersect(
+    ThreadProfilingFeatures a1, Ts... as) {
+  static_assert((true && ... &&
+                 std::is_same_v<std::remove_cv_t<std::remove_reference_t<Ts>>,
+                                ThreadProfilingFeatures>));
+  return static_cast<ThreadProfilingFeatures>(
+      (static_cast<std::underlying_type_t<ThreadProfilingFeatures>>(a1) & ... &
+       static_cast<std::underlying_type_t<ThreadProfilingFeatures>>(as)));
+}
+
+// Are there features in common between the two given sets?
+// Mostly useful to test if any of a set of features is present in another set.
+template <typename... Ts>
+[[nodiscard]] constexpr bool DoFeaturesIntersect(ThreadProfilingFeatures a1,
+                                                 ThreadProfilingFeatures a2) {
+  return Intersect(a1, a2) != ThreadProfilingFeatures::NotProfiled;
+}
+
+namespace mozilla::profiler {
+
+// All data members related to thread profiling are stored here.
+// See derived classes below, which give limited unlocked/locked read/write
+// access in different situations, and will be available through
+// ThreadRegistration and ThreadRegistry.
+class ThreadRegistrationData {
+ public:
+  // No public accessors here. See derived classes for accessors, and
+  // Get.../With... functions for who can use these accessors.
+
+  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
+    // Not including data that is not fully owned here.
+    return 0;
+  }
+
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  static constexpr size_t MAX_JS_FRAMES = 1024;
+  using JsFrame = JS::ProfilingFrameIterator::Frame;
+  using JsFrameBuffer = JsFrame[MAX_JS_FRAMES];
+
+  // `protected` to allow derived classes to read all data members.
+ protected:
+  ThreadRegistrationData(const char* aName, const void* aStackTop);
+
+#ifdef DEBUG
+  // Destructor only used to check invariants.
+  ~ThreadRegistrationData() {
+    MOZ_ASSERT((mProfilingFeatures != ThreadProfilingFeatures::NotProfiled) ==
+               !!mProfiledThreadData);
+    MOZ_ASSERT(!mProfiledThreadData,
+               "mProfiledThreadData pointer should have been reset before "
+               "~ThreadRegistrationData");
+  }
+#endif  // DEBUG
+
+  // Permanent thread information.
+  // Set at construction, read from anywhere, moved-from at destruction.
+  ThreadRegistrationInfo mInfo;
+
+  // Contains profiler labels and JS frames.
+  // Deep-written on thread only, deep-read from thread and suspended thread.
+  ProfilingStack mProfilingStack;
+
+  // In practice, only read from thread and suspended thread.
+  PlatformData mPlatformData;
+
+  // Only read from thread and suspended thread.
+  const void* const mStackTop;
+
+  // Written from thread, read from thread and suspended thread.
+  nsCOMPtr<nsIThread> mThread;
+
+  // If this is a JS thread, this is its JSContext, which is required for any
+  // JS sampling.
+  // Written from thread, read from thread and suspended thread.
+  JSContext* mJSContext = nullptr;
+
+  // If mJSContext is not null AND the thread is being profiled, this points at
+  // the start of a JsFrameBuffer to be used for on-thread synchronous sampling.
+  JsFrame* mJsFrameBuffer = nullptr;
+
+  // The profiler needs to start and stop JS sampling of JS threads at various
+  // times. However, the JS engine can only do the required actions on the
+  // JS thread itself ("on-thread"), not from another thread ("off-thread").
+  // Therefore, we have the following two-step process.
+  //
+  // - The profiler requests (on-thread or off-thread) that the JS sampling be
+  //   started/stopped, by changing mJSSampling to the appropriate REQUESTED
+  //   state.
+  //
+  // - The relevant JS thread polls (on-thread) for changes to mJSSampling.
+  //   When it sees a REQUESTED state, it performs the appropriate actions to
+  //   actually start/stop JS sampling, and changes mJSSampling out of the
+  //   REQUESTED state.
+  //
+  // The state machine is as follows.
+  //
+  //             INACTIVE --> ACTIVE_REQUESTED
+  //                  ^       ^ |
+  //                  |     _/  |
+  //                  |   _/    |
+  //                  |  /      |
+  //                  | v       v
+  //   INACTIVE_REQUESTED <-- ACTIVE
+  //
+  // The polling is done in the following two ways.
+  //
+  // - Via the interrupt callback mechanism; the JS thread must call
+  //   profiler_js_interrupt_callback() from its own interrupt callback.
+  //   This is how sampling must be started/stopped for threads where the
+  //   request was made off-thread.
+  //
+  // - When {Start,Stop}JSSampling() is called on-thread, we can immediately
+  //   follow it with a PollJSSampling() call to avoid the delay between the
+  //   two steps. Likewise, setJSContext() calls PollJSSampling().
+  //
+  // One non-obvious thing about all this: these JS sampling requests are made
+  // on all threads, even non-JS threads. mContext needs to also be set (via
+  // setJSContext(), which can only happen for JS threads) for any JS sampling
+  // to actually happen.
+  //
+  enum {
+    INACTIVE = 0,
+    ACTIVE_REQUESTED = 1,
+    ACTIVE = 2,
+    INACTIVE_REQUESTED = 3,
+  } mJSSampling = INACTIVE;
+
+  uint32_t mJSFlags = 0;
+
+  // Flags to conveniently track various JS instrumentations.
+  enum class JSInstrumentationFlags {
+    StackSampling = 0x1,
+    Allocations = 0x2,
+  };
+
+  [[nodiscard]] bool JSAllocationsEnabled() const {
+    return mJSFlags & uint32_t(JSInstrumentationFlags::Allocations);
+  }
+
+  // The following members may be modified from another thread.
+  // They need to be atomic, because LockData() does not prevent reads from
+  // the owning thread.
+
+  // mSleep tracks whether the thread is sleeping, and if so, whether it has
+  // been previously observed. This is used for an optimization: in some
+  // cases, when a thread is asleep, we duplicate the previous sample, which
+  // is cheaper than taking a new sample.
+  //
+  // mSleep is atomic because it is accessed from multiple threads.
+  //
+  // - It is written only by this thread, via setSleeping() and setAwake().
+  //
+  // - It is read by SamplerThread::Run().
+  //
+  // There are two cases where racing between threads can cause an issue.
+  //
+  // - If CanDuplicateLastSampleDueToSleep() returns false but that result is
+  //   invalidated before being acted upon, we will take a full sample
+  //   unnecessarily. This is additional work but won't cause any correctness
+  //   issues. (In actual fact, this case is impossible. In order to go from
+  //   CanDuplicateLastSampleDueToSleep() returning false to it returning true
+  //   requires an intermediate call to it in order for mSleep to go from
+  //   SLEEPING_NOT_OBSERVED to SLEEPING_OBSERVED.)
+  //
+  // - If CanDuplicateLastSampleDueToSleep() returns true but that result is
+  //   invalidated before being acted upon -- i.e. the thread wakes up before
+  //   DuplicateLastSample() is called -- we will duplicate the previous
+  //   sample. This is inaccurate, but only slightly... we will effectively
+  //   treat the thread as having slept a tiny bit longer than it really did.
+  //
+  // This latter inaccuracy could be avoided by moving the
+  // CanDuplicateLastSampleDueToSleep() check within the thread-freezing code,
+  // e.g. the section where Tick() is called. But that would reduce the
+  // effectiveness of the optimization because more code would have to be run
+  // before we can tell that duplication is allowed.
+  //
+  static const int AWAKE = 0;
+  static const int SLEEPING_NOT_OBSERVED = 1;
+  static const int SLEEPING_OBSERVED = 2;
+  // Read&written from thread and suspended thread.
+  Atomic<int> mSleep{AWAKE};
+  Atomic<uint64_t> mThreadCpuTimeInNsAtLastSleep{0};
+
+#ifdef NIGHTLY_BUILD
+  // The first wake is the thread creation.
+  Atomic<uint64_t, MemoryOrdering::Relaxed> mWakeCount{1};
+  mutable baseprofiler::detail::BaseProfilerMutex mRecordWakeCountMutex;
+  mutable uint64_t mAlreadyRecordedWakeCount = 0;
+  mutable uint64_t mAlreadyRecordedCpuTimeInMs = 0;
+#endif
+
+  // Is this thread currently being profiled, and with which features?
+  // Written from profiler, read from any thread.
+  // Invariant: `!!mProfilingFeatures == !!mProfiledThreadData` (set together.)
+  Atomic<ThreadProfilingFeatures, MemoryOrdering::Relaxed> mProfilingFeatures{
+      ThreadProfilingFeatures::NotProfiled};
+
+  // If the profiler is active and this thread is selected for profiling, this
+  // points at the relevant ProfiledThreadData.
+  // Fully controlled by the profiler.
+  // Invariant: `!!mProfilingFeatures == !!mProfiledThreadData` (set together).
+  ProfiledThreadData* mProfiledThreadData = nullptr;
+};
+
+// Accessing const data from any thread.
+class ThreadRegistrationUnlockedConstReader : public ThreadRegistrationData {
+ public:
+  [[nodiscard]] const ThreadRegistrationInfo& Info() const { return mInfo; }
+
+  [[nodiscard]] const PlatformData& PlatformDataCRef() const {
+    return mPlatformData;
+  }
+
+  [[nodiscard]] const void* StackTop() const { return mStackTop; }
+
+ protected:
+  ThreadRegistrationUnlockedConstReader(const char* aName,
+                                        const void* aStackTop)
+      : ThreadRegistrationData(aName, aStackTop) {}
+};
+
+// Accessing atomic data from any thread.
+class ThreadRegistrationUnlockedConstReaderAndAtomicRW
+    : public ThreadRegistrationUnlockedConstReader {
+ public:
+  [[nodiscard]] const ProfilingStack& ProfilingStackCRef() const {
+    return mProfilingStack;
+  }
+  [[nodiscard]] ProfilingStack& ProfilingStackRef() { return mProfilingStack; }
+
+  // Similar to `profiler_is_active()`, this atomic flag may become out-of-date.
+  // It should only be used as an indication to know whether this thread is
+  // probably being profiled (with some specific features), to avoid doing
+  // expensive operations otherwise. Edge cases:
+  // - This thread could get `NotProfiled`, but the profiler has just started,
+  //   so some very early data may be missing. No real impact on profiling.
+  // - This thread could see profiled features, but the profiled has just
+  //   stopped, so some some work will be done and then discarded when finally
+  //   attempting to write to the buffer. No impact on profiling.
+  // - This thread could see profiled features, but the profiler will quickly
+  //   stop and restart, so this thread will write information relevant to the
+  //   previous profiling session. Very rare, and little impact on profiling.
+  [[nodiscard]] ThreadProfilingFeatures ProfilingFeatures() const {
+    return mProfilingFeatures;
+  }
+
+  // Call this whenever the current thread sleeps. Calling it twice in a row
+  // without an intervening setAwake() call is an error.
+  void SetSleeping() {
+    MOZ_ASSERT(mSleep == AWAKE);
+    mSleep = SLEEPING_NOT_OBSERVED;
+  }
+
+  // Call this whenever the current thread wakes. Calling it twice in a row
+  // without an intervening setSleeping() call is an error.
+  void SetAwake() {
+    MOZ_ASSERT(mSleep != AWAKE);
+    mSleep = AWAKE;
+#ifdef NIGHTLY_BUILD
+    ++mWakeCount;
+#endif
+  }
+
+  // Returns the CPU time used by the thread since the previous call to this
+  // method or since the thread was started if this is the first call.
+  uint64_t GetNewCpuTimeInNs() {
+    uint64_t newCpuTimeNs;
+    if (!GetCpuTimeSinceThreadStartInNs(&newCpuTimeNs, PlatformDataCRef())) {
+      newCpuTimeNs = 0;
+    }
+    uint64_t before = mThreadCpuTimeInNsAtLastSleep;
+    uint64_t result =
+        MOZ_LIKELY(newCpuTimeNs > before) ? newCpuTimeNs - before : 0;
+    mThreadCpuTimeInNsAtLastSleep = newCpuTimeNs;
+    return result;
+  }
+
+#ifdef NIGHTLY_BUILD
+  void RecordWakeCount() const;
+#endif
+
+  // This is called on every profiler restart. Put things that should happen
+  // at that time here.
+  void ReinitializeOnResume() {
+    // This is needed to cause an initial sample to be taken from sleeping
+    // threads that had been observed prior to the profiler stopping and
+    // restarting. Otherwise sleeping threads would not have any samples to
+    // copy forward while sleeping.
+    (void)mSleep.compareExchange(SLEEPING_OBSERVED, SLEEPING_NOT_OBSERVED);
+  }
+
+  // This returns true for the second and subsequent calls in each sleep
+  // cycle, so that the sampler can skip its full sampling and reuse the first
+  // asleep sample instead.
+  [[nodiscard]] bool CanDuplicateLastSampleDueToSleep() {
+    if (mSleep == AWAKE) {
+      return false;
+    }
+    if (mSleep.compareExchange(SLEEPING_NOT_OBSERVED, SLEEPING_OBSERVED)) {
+      return false;
+    }
+    return true;
+  }
+
+  [[nodiscard]] bool IsSleeping() const { return mSleep != AWAKE; }
+
+ protected:
+  ThreadRegistrationUnlockedConstReaderAndAtomicRW(const char* aName,
+                                                   const void* aStackTop)
+      : ThreadRegistrationUnlockedConstReader(aName, aStackTop) {}
+};
+
+// Like above, with special PSAutoLock-guarded accessors.
+class ThreadRegistrationUnlockedRWForLockedProfiler
+    : public ThreadRegistrationUnlockedConstReaderAndAtomicRW {
+ public:
+  // IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT!
+  // Only add functions that take a `const PSAutoLock&` proof-of-lock.
+  // (Because there is no other lock.)
+
+  [[nodiscard]] const ProfiledThreadData* GetProfiledThreadData(
+      const PSAutoLock&) const {
+    return mProfiledThreadData;
+  }
+
+  [[nodiscard]] ProfiledThreadData* GetProfiledThreadData(const PSAutoLock&) {
+    return mProfiledThreadData;
+  }
+
+ protected:
+  ThreadRegistrationUnlockedRWForLockedProfiler(const char* aName,
+                                                const void* aStackTop)
+      : ThreadRegistrationUnlockedConstReaderAndAtomicRW(aName, aStackTop) {}
+};
+
+// Reading data, unlocked from the thread, or locked otherwise.
+// This data MUST only be written from the thread with lock (i.e., in
+// LockedRWOnThread through RWOnThreadWithLock.)
+class ThreadRegistrationUnlockedReaderAndAtomicRWOnThread
+    : public ThreadRegistrationUnlockedRWForLockedProfiler {
+ public:
+  // IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT!
+  // Non-atomic members read here MUST be written from LockedRWOnThread (to
+  // guarantee that they are only modified on this thread.)
+
+  [[nodiscard]] JSContext* GetJSContext() const { return mJSContext; }
+
+ protected:
+  ThreadRegistrationUnlockedReaderAndAtomicRWOnThread(const char* aName,
+                                                      const void* aStackTop)
+      : ThreadRegistrationUnlockedRWForLockedProfiler(aName, aStackTop) {}
+};
+
+// Accessing locked data from the thread, or from any thread through the locked
+// profiler:
+
+// Like above, and profiler can also read&write mutex-protected members.
+class ThreadRegistrationLockedRWFromAnyThread
+    : public ThreadRegistrationUnlockedReaderAndAtomicRWOnThread {
+ public:
+  void SetProfilingFeaturesAndData(ThreadProfilingFeatures aProfilingFeatures,
+                                   ProfiledThreadData* aProfiledThreadData,
+                                   const PSAutoLock&);
+  void ClearProfilingFeaturesAndData(const PSAutoLock&);
+
+  // Not null when JSContext is not null AND this thread is being profiled.
+  // Points at the start of JsFrameBuffer.
+  [[nodiscard]] JsFrame* GetJsFrameBuffer() const { return mJsFrameBuffer; }
+
+  [[nodiscard]] const nsCOMPtr<nsIEventTarget> GetEventTarget() const {
+    return mThread;
+  }
+
+  void ResetMainThread(nsIThread* aThread) { mThread = aThread; }
+
+  // aDelay is the time the event that is currently running on the thread was
+  // queued before starting to run (if a PrioritizedEventQueue
+  // (i.e. MainThread), this will be 0 for any event at a lower priority
+  // than Input).
+  // aRunning is the time the event has been running. If no event is running
+  // these will both be TimeDuration() (i.e. 0). Both are out params, and are
+  // always set. Their initial value is discarded.
+  void GetRunningEventDelay(const TimeStamp& aNow, TimeDuration& aDelay,
+                            TimeDuration& aRunning) {
+    if (mThread) {  // can be null right at the start of a process
+      TimeStamp start;
+      mThread->GetRunningEventDelay(&aDelay, &start);
+      if (!start.IsNull()) {
+        // Note: the timestamp used here will be from when we started to
+        // suspend and sample the thread; which is also the timestamp
+        // associated with the sample.
+        aRunning = aNow - start;
+        return;
+      }
+    }
+    aDelay = TimeDuration();
+    aRunning = TimeDuration();
+  }
+
+  // Request that this thread start JS sampling. JS sampling won't actually
+  // start until a subsequent PollJSSampling() call occurs *and* mContext has
+  // been set.
+  void StartJSSampling(uint32_t aJSFlags) {
+    // This function runs on-thread or off-thread.
+
+    MOZ_RELEASE_ASSERT(mJSSampling == INACTIVE ||
+                       mJSSampling == INACTIVE_REQUESTED);
+    mJSSampling = ACTIVE_REQUESTED;
+    mJSFlags = aJSFlags;
+  }
+
+  // Request that this thread stop JS sampling. JS sampling won't actually
+  // stop until a subsequent PollJSSampling() call occurs.
+  void StopJSSampling() {
+    // This function runs on-thread or off-thread.
+
+    MOZ_RELEASE_ASSERT(mJSSampling == ACTIVE ||
+                       mJSSampling == ACTIVE_REQUESTED);
+    mJSSampling = INACTIVE_REQUESTED;
+  }
+
+ protected:
+  ThreadRegistrationLockedRWFromAnyThread(const char* aName,
+                                          const void* aStackTop)
+      : ThreadRegistrationUnlockedReaderAndAtomicRWOnThread(aName, aStackTop) {}
+};
+
+// Accessing data, locked, from the thread.
+// If any non-atomic data is readable from UnlockedReaderAndAtomicRWOnThread,
+// it must be written from here, and not in base classes: Since this data is
+// only written on the thread, it can be read from the same thread without
+// lock; but writing must be locked so that other threads can safely read it,
+// typically from LockedRWFromAnyThread.
+class ThreadRegistrationLockedRWOnThread
+    : public ThreadRegistrationLockedRWFromAnyThread {
+ public:
+  void SetJSContext(JSContext* aJSContext);
+  void ClearJSContext();
+
+  // Poll to see if JS sampling should be started/stopped.
+  void PollJSSampling();
+
+ public:
+  ThreadRegistrationLockedRWOnThread(const char* aName, const void* aStackTop)
+      : ThreadRegistrationLockedRWFromAnyThread(aName, aStackTop) {}
+};
+
+}  // namespace mozilla::profiler
+
+#endif  // ProfilerThreadRegistrationData_h
diff --git a/tools/profiler/public/ProfilerThreadRegistrationInfo.h b/tools/profiler/public/ProfilerThreadRegistrationInfo.h
new file mode 100644
index 0000000000..e116c3059e
--- /dev/null
+++ b/tools/profiler/public/ProfilerThreadRegistrationInfo.h
@@ -0,0 +1,64 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerThreadRegistrationInfo_h
+#define ProfilerThreadRegistrationInfo_h
+
+#include "mozilla/BaseAndGeckoProfilerDetail.h"
+#include "mozilla/ProfilerUtils.h"
+#include "mozilla/TimeStamp.h"
+
+#include <string>
+
+namespace mozilla::profiler {
+
+// This class contains immutable information about a thread which needs to be
+// stored across restarts of the profiler and which can be useful even after the
+// thread has stopped running.
+class ThreadRegistrationInfo {
+ public:
+  // Construct on the thread.
+  explicit ThreadRegistrationInfo(const char* aName) : mName(aName) {}
+
+  // Construct for a foreign thread (e.g., Java).
+  ThreadRegistrationInfo(const char* aName, ProfilerThreadId aThreadId,
+                         bool aIsMainThread, const TimeStamp& aRegisterTime)
+      : mName(aName),
+        mRegisterTime(aRegisterTime),
+        mThreadId(aThreadId),
+        mIsMainThread(aIsMainThread) {}
+
+  // Only allow move construction, for extraction when the thread ends.
+  ThreadRegistrationInfo(ThreadRegistrationInfo&&) = default;
+
+  // Other copies/moves disallowed.
+  ThreadRegistrationInfo(const ThreadRegistrationInfo&) = delete;
+  ThreadRegistrationInfo& operator=(const ThreadRegistrationInfo&) = delete;
+  ThreadRegistrationInfo& operator=(ThreadRegistrationInfo&&) = delete;
+
+  [[nodiscard]] const char* Name() const { return mName.c_str(); }
+  [[nodiscard]] const TimeStamp& RegisterTime() const { return mRegisterTime; }
+  [[nodiscard]] ProfilerThreadId ThreadId() const { return mThreadId; }
+  [[nodiscard]] bool IsMainThread() const { return mIsMainThread; }
+
+ private:
+  static TimeStamp ExistingRegisterTimeOrNow() {
+    TimeStamp registerTime = baseprofiler::detail::GetThreadRegistrationTime();
+    if (!registerTime) {
+      registerTime = TimeStamp::Now();
+    }
+    return registerTime;
+  }
+
+  const std::string mName;
+  const TimeStamp mRegisterTime = ExistingRegisterTimeOrNow();
+  const ProfilerThreadId mThreadId = profiler_current_thread_id();
+  const bool mIsMainThread = profiler_is_main_thread();
+};
+
+}  // namespace mozilla::profiler
+
+#endif  // ProfilerThreadRegistrationInfo_h
diff --git a/tools/profiler/public/ProfilerThreadRegistry.h b/tools/profiler/public/ProfilerThreadRegistry.h
new file mode 100644
index 0000000000..4d0fd3ef68
--- /dev/null
+++ b/tools/profiler/public/ProfilerThreadRegistry.h
@@ -0,0 +1,321 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerThreadRegistry_h
+#define ProfilerThreadRegistry_h
+
+#include "mozilla/BaseProfilerDetail.h"
+#include "mozilla/ProfilerThreadRegistration.h"
+#include "mozilla/Vector.h"
+
+namespace mozilla::profiler {
+
+class ThreadRegistry {
+ private:
+  using RegistryMutex = baseprofiler::detail::BaseProfilerSharedMutex;
+  using RegistryLockExclusive =
+      baseprofiler::detail::BaseProfilerAutoLockExclusive;
+  using RegistryLockShared = baseprofiler::detail::BaseProfilerAutoLockShared;
+
+ public:
+  // Aliases to data accessors (removing the ThreadRegistration prefix).
+
+  using UnlockedConstReader = ThreadRegistrationUnlockedConstReader;
+  using UnlockedConstReaderAndAtomicRW =
+      ThreadRegistrationUnlockedConstReaderAndAtomicRW;
+  using UnlockedRWForLockedProfiler =
+      ThreadRegistrationUnlockedRWForLockedProfiler;
+  using UnlockedReaderAndAtomicRWOnThread =
+      ThreadRegistrationUnlockedReaderAndAtomicRWOnThread;
+  using LockedRWFromAnyThread = ThreadRegistrationLockedRWFromAnyThread;
+  using LockedRWOnThread = ThreadRegistrationLockedRWOnThread;
+
+  // Off-thread access through the registry, providing the following data
+  // accessors: UnlockedConstReader, UnlockedConstReaderAndAtomicRW,
+  // UnlockedRWForLockedProfiler, and LockedRWFromAnyThread.
+  // (See ThreadRegistration class for ON-thread access.)
+
+  // Reference-like class pointing at a ThreadRegistration.
+  // It should only exist while sRegistryMutex is locked.
+  class OffThreadRef {
+   public:
+    // const UnlockedConstReader
+
+    [[nodiscard]] const UnlockedConstReader& UnlockedConstReaderCRef() const {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedConstReader(F&& aF) const {
+      return std::forward<F>(aF)(UnlockedConstReaderCRef());
+    }
+
+    // const UnlockedConstReaderAndAtomicRW
+
+    [[nodiscard]] const UnlockedConstReaderAndAtomicRW&
+    UnlockedConstReaderAndAtomicRWCRef() const {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedConstReaderAndAtomicRW(F&& aF) const {
+      return std::forward<F>(aF)(UnlockedConstReaderAndAtomicRWCRef());
+    }
+
+    // UnlockedConstReaderAndAtomicRW
+
+    [[nodiscard]] UnlockedConstReaderAndAtomicRW&
+    UnlockedConstReaderAndAtomicRWRef() {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedConstReaderAndAtomicRW(F&& aF) {
+      return std::forward<F>(aF)(UnlockedConstReaderAndAtomicRWRef());
+    }
+
+    // const UnlockedRWForLockedProfiler
+
+    [[nodiscard]] const UnlockedRWForLockedProfiler&
+    UnlockedRWForLockedProfilerCRef() const {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedRWForLockedProfiler(F&& aF) const {
+      return std::forward<F>(aF)(UnlockedRWForLockedProfilerCRef());
+    }
+
+    // UnlockedRWForLockedProfiler
+
+    [[nodiscard]] UnlockedRWForLockedProfiler&
+    UnlockedRWForLockedProfilerRef() {
+      return mThreadRegistration->mData;
+    }
+
+    template <typename F>
+    auto WithUnlockedRWForLockedProfiler(F&& aF) {
+      return std::forward<F>(aF)(UnlockedRWForLockedProfilerRef());
+    }
+
+    // const LockedRWFromAnyThread through ConstRWFromAnyThreadWithLock
+
+    class ConstRWFromAnyThreadWithLock {
+     public:
+      [[nodiscard]] const LockedRWFromAnyThread& DataCRef() const {
+        return mLockedRWFromAnyThread;
+      }
+      [[nodiscard]] const LockedRWFromAnyThread* operator->() const {
+        return &mLockedRWFromAnyThread;
+      }
+
+      ConstRWFromAnyThreadWithLock(
+          const LockedRWFromAnyThread& aLockedRWFromAnyThread,
+          ThreadRegistration::DataMutex& aDataMutex)
+          : mLockedRWFromAnyThread(aLockedRWFromAnyThread),
+            mDataLock(aDataMutex) {}
+
+     private:
+      const LockedRWFromAnyThread& mLockedRWFromAnyThread;
+      ThreadRegistration::DataLock mDataLock;
+    };
+
+    [[nodiscard]] ConstRWFromAnyThreadWithLock ConstLockedRWFromAnyThread()
+        const {
+      return ConstRWFromAnyThreadWithLock{mThreadRegistration->mData,
+                                          mThreadRegistration->mDataMutex};
+    }
+
+    template <typename F>
+    auto WithConstLockedRWFromAnyThread(F&& aF) const {
+      ConstRWFromAnyThreadWithLock lockedData = ConstLockedRWFromAnyThread();
+      return std::forward<F>(aF)(lockedData.DataCRef());
+    }
+
+    // LockedRWFromAnyThread through RWFromAnyThreadWithLock
+
+    class RWFromAnyThreadWithLock {
+     public:
+      [[nodiscard]] const LockedRWFromAnyThread& DataCRef() const {
+        return mLockedRWFromAnyThread;
+      }
+      [[nodiscard]] LockedRWFromAnyThread& DataRef() {
+        return mLockedRWFromAnyThread;
+      }
+      [[nodiscard]] const LockedRWFromAnyThread* operator->() const {
+        return &mLockedRWFromAnyThread;
+      }
+      [[nodiscard]] LockedRWFromAnyThread* operator->() {
+        return &mLockedRWFromAnyThread;
+      }
+
+      // In some situations, it may be useful to do some on-thread operations if
+      // we are indeed on this thread now. The lock is still held here; caller
+      // should not use this pointer longer than this RWFromAnyThreadWithLock.
+      [[nodiscard]] LockedRWOnThread* GetLockedRWOnThread() {
+        if (mLockedRWFromAnyThread.Info().ThreadId() ==
+            profiler_current_thread_id()) {
+          // mLockedRWFromAnyThread references a subclass of the
+          // ThreadRegistration's mData, so it's safe to downcast it to another
+          // hierarchy level of the object.
+          return &static_cast<LockedRWOnThread&>(mLockedRWFromAnyThread);
+        }
+        return nullptr;
+      }
+
+     private:
+      friend class OffThreadRef;
+      RWFromAnyThreadWithLock(LockedRWFromAnyThread& aLockedRWFromAnyThread,
+                              ThreadRegistration::DataMutex& aDataMutex)
+          : mLockedRWFromAnyThread(aLockedRWFromAnyThread),
+            mDataLock(aDataMutex) {}
+
+      LockedRWFromAnyThread& mLockedRWFromAnyThread;
+      ThreadRegistration::DataLock mDataLock;
+    };
+
+    [[nodiscard]] RWFromAnyThreadWithLock GetLockedRWFromAnyThread() {
+      return RWFromAnyThreadWithLock{mThreadRegistration->mData,
+                                     mThreadRegistration->mDataMutex};
+    }
+
+    template <typename F>
+    auto WithLockedRWFromAnyThread(F&& aF) {
+      RWFromAnyThreadWithLock lockedData = GetLockedRWFromAnyThread();
+      return std::forward<F>(aF)(lockedData.DataRef());
+    }
+
+   private:
+    // Only ThreadRegistry should construct an OnThreadRef.
+    friend class ThreadRegistry;
+    explicit OffThreadRef(ThreadRegistration& aThreadRegistration)
+        : mThreadRegistration(&aThreadRegistration) {}
+
+    // If we have an ON-thread ref, it's safe to convert to an OFF-thread ref.
+    explicit OffThreadRef(ThreadRegistration::OnThreadRef aOnThreadRef)
+        : mThreadRegistration(aOnThreadRef.mThreadRegistration) {}
+
+    [[nodiscard]] bool IsPointingAt(
+        ThreadRegistration& aThreadRegistration) const {
+      return mThreadRegistration == &aThreadRegistration;
+    }
+
+    // Guaranted to be non-null by construction.
+    ThreadRegistration* mThreadRegistration;
+  };
+
+  // Lock the registry non-exclusively and allow iteration. E.g.:
+  // `for (OffThreadRef thread : LockedRegistry{}) { ... }`
+  // Do *not* export copies/references, as they could become dangling.
+  // Locking order: Profiler, ThreadRegistry, ThreadRegistration.
+  class LockedRegistry {
+   public:
+    LockedRegistry()
+        : mRegistryLock([]() -> RegistryMutex& {
+            MOZ_ASSERT(!IsRegistryMutexLockedOnCurrentThread(),
+                       "Recursive locking detected");
+            // In DEBUG builds, *before* we attempt to lock sRegistryMutex, we
+            // want to check that the ThreadRegistration mutex is *not* locked
+            // on this thread, to avoid inversion deadlocks.
+            MOZ_ASSERT(!ThreadRegistration::IsDataMutexLockedOnCurrentThread());
+            return sRegistryMutex;
+          }()) {
+      ThreadRegistration::WithOnThreadRef(
+          [](ThreadRegistration::OnThreadRef aOnThreadRef) {
+            aOnThreadRef.mThreadRegistration
+                ->mIsRegistryLockedSharedOnThisThread = true;
+          });
+    }
+
+    ~LockedRegistry() {
+      ThreadRegistration::WithOnThreadRef(
+          [](ThreadRegistration::OnThreadRef aOnThreadRef) {
+            aOnThreadRef.mThreadRegistration
+                ->mIsRegistryLockedSharedOnThisThread = false;
+          });
+    }
+
+    [[nodiscard]] const OffThreadRef* begin() const {
+      return sRegistryContainer.begin();
+    }
+    [[nodiscard]] OffThreadRef* begin() { return sRegistryContainer.begin(); }
+    [[nodiscard]] const OffThreadRef* end() const {
+      return sRegistryContainer.end();
+    }
+    [[nodiscard]] OffThreadRef* end() { return sRegistryContainer.end(); }
+
+   private:
+    RegistryLockShared mRegistryLock;
+  };
+
+  // Call `F(OffThreadRef)` for the given aThreadId.
+  template <typename F>
+  static void WithOffThreadRef(ProfilerThreadId aThreadId, F&& aF) {
+    for (OffThreadRef thread : LockedRegistry{}) {
+      if (thread.UnlockedConstReaderCRef().Info().ThreadId() == aThreadId) {
+        std::forward<F>(aF)(thread);
+        break;
+      }
+    }
+  }
+
+  template <typename F, typename FallbackReturn>
+  [[nodiscard]] static auto WithOffThreadRefOr(ProfilerThreadId aThreadId,
+                                               F&& aF,
+                                               FallbackReturn&& aFallbackReturn)
+      -> decltype(std::forward<F>(aF)(std::declval<OffThreadRef>())) {
+    for (OffThreadRef thread : LockedRegistry{}) {
+      if (thread.UnlockedConstReaderCRef().Info().ThreadId() == aThreadId) {
+        return std::forward<F>(aF)(thread);
+      }
+    }
+    return std::forward<FallbackReturn>(aFallbackReturn);
+  }
+
+  static size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) {
+    LockedRegistry lockedRegistry;
+    // "Ex" because we don't count static objects, but we count whatever they
+    // allocated on the heap.
+    size_t bytes = sRegistryContainer.sizeOfExcludingThis(aMallocSizeOf);
+    for (const OffThreadRef& offThreadRef : lockedRegistry) {
+      bytes +=
+          offThreadRef.mThreadRegistration->SizeOfExcludingThis(aMallocSizeOf);
+    }
+    return bytes;
+  }
+
+  static size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) {
+    return SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  [[nodiscard]] static bool IsRegistryMutexLockedOnCurrentThread() {
+    return sRegistryMutex.IsLockedExclusiveOnCurrentThread() ||
+           ThreadRegistration::WithOnThreadRefOr(
+               [](ThreadRegistration::OnThreadRef aOnThreadRef) {
+                 return aOnThreadRef.mThreadRegistration
+                     ->mIsRegistryLockedSharedOnThisThread;
+               },
+               false);
+  }
+
+ private:
+  using RegistryContainer = Vector<OffThreadRef>;
+
+  static RegistryContainer sRegistryContainer;
+
+  // Mutex protecting the registry.
+  // Locking order: Profiler, ThreadRegistry, ThreadRegistration.
+  static RegistryMutex sRegistryMutex;
+
+  // Only allow ThreadRegistration to (un)register itself.
+  friend class ThreadRegistration;
+  static void Register(ThreadRegistration::OnThreadRef aOnThreadRef);
+  static void Unregister(ThreadRegistration::OnThreadRef aOnThreadRef);
+};
+
+}  // namespace mozilla::profiler
+
+#endif  // ProfilerThreadRegistry_h
diff --git a/tools/profiler/public/ProfilerThreadSleep.h b/tools/profiler/public/ProfilerThreadSleep.h
new file mode 100644
index 0000000000..730176d39f
--- /dev/null
+++ b/tools/profiler/public/ProfilerThreadSleep.h
@@ -0,0 +1,58 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// APIs that inform the profiler when a thread is effectively asleep so that we
+// can avoid sampling it more than once.
+
+#ifndef ProfilerThreadSleep_h
+#define ProfilerThreadSleep_h
+
+#ifndef MOZ_GECKO_PROFILER
+
+// This file can be #included unconditionally. However, everything within this
+// file must be guarded by a #ifdef MOZ_GECKO_PROFILER, *except* for the
+// following macros and functions, which encapsulate the most common operations
+// and thus avoid the need for many #ifdefs.
+
+#  define AUTO_PROFILER_THREAD_SLEEP
+
+static inline void profiler_thread_sleep() {}
+
+static inline void profiler_thread_wake() {}
+
+#else  // !MOZ_GECKO_PROFILER
+
+#  include "mozilla/Attributes.h"
+#  include "mozilla/BaseProfilerRAIIMacro.h"
+
+// These functions tell the profiler that a thread went to sleep so that we can
+// avoid sampling it more than once while it's sleeping. Calling
+// profiler_thread_sleep() twice without an intervening profiler_thread_wake()
+// is an error. All three functions operate the same whether the profiler is
+// active or inactive.
+void profiler_thread_sleep();
+void profiler_thread_wake();
+
+// Mark a thread as asleep within a scope.
+// (See also AUTO_PROFILER_THREAD_WAKE in ProfilerThreadState.h)
+#  define AUTO_PROFILER_THREAD_SLEEP \
+    mozilla::AutoProfilerThreadSleep PROFILER_RAII
+
+namespace mozilla {
+
+// (See also AutoProfilerThreadWake in ProfilerThreadState.h)
+class MOZ_RAII AutoProfilerThreadSleep {
+ public:
+  explicit AutoProfilerThreadSleep() { profiler_thread_sleep(); }
+
+  ~AutoProfilerThreadSleep() { profiler_thread_wake(); }
+};
+
+}  // namespace mozilla
+
+#endif  // !MOZ_GECKO_PROFILER
+
+#endif  // ProfilerThreadSleep_h
diff --git a/tools/profiler/public/ProfilerThreadState.h b/tools/profiler/public/ProfilerThreadState.h
new file mode 100644
index 0000000000..6ac48e41dd
--- /dev/null
+++ b/tools/profiler/public/ProfilerThreadState.h
@@ -0,0 +1,128 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This header contains functions that give information about the Profiler state
+// with regards to the current thread.
+
+#ifndef ProfilerThreadState_h
+#define ProfilerThreadState_h
+
+#include "mozilla/ProfilerState.h"
+#include "mozilla/ProfilerThreadRegistration.h"
+#include "mozilla/ProfilerThreadRegistry.h"
+#include "mozilla/ProfilerThreadSleep.h"
+
+// During profiling, if the current thread is registered, return true
+// (regardless of whether it is actively being profiled).
+// (Same caveats and recommended usage as profiler_is_active().)
+[[nodiscard]] inline bool profiler_is_active_and_thread_is_registered() {
+  return profiler_is_active() &&
+         mozilla::profiler::ThreadRegistration::IsRegistered();
+}
+
+// Is the profiler active and unpaused, and is the current thread being
+// profiled for any of the given features? (Same caveats and recommended usage
+// as profiler_is_active().)
+[[nodiscard]] inline bool profiler_thread_is_being_profiled(
+    ThreadProfilingFeatures aThreadProfilingFeatures) {
+  return profiler_is_active_and_unpaused() &&
+         mozilla::profiler::ThreadRegistration::WithOnThreadRefOr(
+             [aThreadProfilingFeatures](
+                 mozilla::profiler::ThreadRegistration::OnThreadRef aTR) {
+               return DoFeaturesIntersect(
+                   aTR.UnlockedConstReaderAndAtomicRWCRef().ProfilingFeatures(),
+                   aThreadProfilingFeatures);
+             },
+             false);
+}
+
+// Is the profiler active and unpaused, and is the given thread being profiled?
+// (Same caveats and recommended usage as profiler_is_active().)
+// Safe to use with the current thread id, or unspecified ProfilerThreadId (same
+// as current thread id).
+[[nodiscard]] inline bool profiler_thread_is_being_profiled(
+    const ProfilerThreadId& aThreadId,
+    ThreadProfilingFeatures aThreadProfilingFeatures) {
+  if (!profiler_is_active_and_unpaused()) {
+    return false;
+  }
+
+  if (!aThreadId.IsSpecified() || aThreadId == profiler_current_thread_id()) {
+    // For the current thread id, use the ThreadRegistration directly, it is
+    // more efficient.
+    return mozilla::profiler::ThreadRegistration::WithOnThreadRefOr(
+        [aThreadProfilingFeatures](
+            mozilla::profiler::ThreadRegistration::OnThreadRef aTR) {
+          return DoFeaturesIntersect(
+              aTR.UnlockedConstReaderAndAtomicRWCRef().ProfilingFeatures(),
+              aThreadProfilingFeatures);
+        },
+        false);
+  }
+
+  // For other threads, go through the ThreadRegistry.
+  return mozilla::profiler::ThreadRegistry::WithOffThreadRefOr(
+      aThreadId,
+      [aThreadProfilingFeatures](
+          mozilla::profiler::ThreadRegistry::OffThreadRef aTR) {
+        return DoFeaturesIntersect(
+            aTR.UnlockedConstReaderAndAtomicRWCRef().ProfilingFeatures(),
+            aThreadProfilingFeatures);
+      },
+      false);
+}
+
+// Is the current thread registered and sleeping?
+[[nodiscard]] inline bool profiler_thread_is_sleeping() {
+  return profiler_is_active() &&
+         mozilla::profiler::ThreadRegistration::WithOnThreadRefOr(
+             [](mozilla::profiler::ThreadRegistration::OnThreadRef aTR) {
+               return aTR.UnlockedConstReaderAndAtomicRWCRef().IsSleeping();
+             },
+             false);
+}
+
+#ifndef MOZ_GECKO_PROFILER
+
+#  define AUTO_PROFILER_THREAD_WAKE
+
+#else  // !MOZ_GECKO_PROFILER
+
+// Mark a thread as awake within a scope.
+// (See also AUTO_PROFILER_THREAD_SLEEP in mozilla/ProfilerThreadSleep.h)
+#  define AUTO_PROFILER_THREAD_WAKE \
+    mozilla::AutoProfilerThreadWake PROFILER_RAII
+
+namespace mozilla {
+
+// Temporarily wake up the profiling of a thread while servicing events such as
+// Asynchronous Procedure Calls (APCs).
+// (See also AutoProfilerThreadSleep in ProfilerThreadSleep.h)
+class MOZ_RAII AutoProfilerThreadWake {
+ public:
+  explicit AutoProfilerThreadWake()
+      : mIssuedWake(profiler_thread_is_sleeping()) {
+    if (mIssuedWake) {
+      profiler_thread_wake();
+    }
+  }
+
+  ~AutoProfilerThreadWake() {
+    if (mIssuedWake) {
+      MOZ_ASSERT(!profiler_thread_is_sleeping());
+      profiler_thread_sleep();
+    }
+  }
+
+ private:
+  bool mIssuedWake;
+};
+
+}  // namespace mozilla
+
+#endif  // !MOZ_GECKO_PROFILER
+
+#endif  // ProfilerThreadState_h
diff --git a/tools/profiler/public/ProfilerUtils.h b/tools/profiler/public/ProfilerUtils.h
new file mode 100644
index 0000000000..3969761e18
--- /dev/null
+++ b/tools/profiler/public/ProfilerUtils.h
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerUtils_h
+#define ProfilerUtils_h
+
+// This header contains most process- and thread-related functions.
+// It is safe to include unconditionally.
+
+#include "mozilla/BaseProfilerUtils.h"
+
+using ProfilerProcessId = mozilla::baseprofiler::BaseProfilerProcessId;
+using ProfilerThreadId = mozilla::baseprofiler::BaseProfilerThreadId;
+
+// Get the current process's ID.
+[[nodiscard]] ProfilerProcessId profiler_current_process_id();
+
+// Get the current thread's ID.
+[[nodiscard]] ProfilerThreadId profiler_current_thread_id();
+
+// Must be called at least once from the main thread, before any other main-
+// thread id function.
+void profiler_init_main_thread_id();
+
+[[nodiscard]] ProfilerThreadId profiler_main_thread_id();
+
+[[nodiscard]] bool profiler_is_main_thread();
+
+#endif  // ProfilerUtils_h
diff --git a/tools/profiler/public/shared-libraries.h b/tools/profiler/public/shared-libraries.h
new file mode 100644
index 0000000000..dfd3599e71
--- /dev/null
+++ b/tools/profiler/public/shared-libraries.h
@@ -0,0 +1,213 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef SHARED_LIBRARIES_H_
+#define SHARED_LIBRARIES_H_
+
+#ifndef MOZ_GECKO_PROFILER
+#  error This header does not have a useful implementation on your platform!
+#endif
+
+#include "nsNativeCharsetUtils.h"
+#include "nsString.h"
+#include <nsID.h>
+
+#include <algorithm>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string>
+#include <vector>
+
+namespace IPC {
+class MessageReader;
+class MessageWriter;
+template <typename T>
+struct ParamTraits;
+}  // namespace IPC
+
+class SharedLibrary {
+ public:
+  SharedLibrary(uintptr_t aStart, uintptr_t aEnd, uintptr_t aOffset,
+                const nsCString& aBreakpadId, const nsCString& aCodeId,
+                const nsString& aModuleName, const nsString& aModulePath,
+                const nsString& aDebugName, const nsString& aDebugPath,
+                const nsCString& aVersion, const char* aArch)
+      : mStart(aStart),
+        mEnd(aEnd),
+        mOffset(aOffset),
+        mBreakpadId(aBreakpadId),
+        mCodeId(aCodeId),
+        mModuleName(aModuleName),
+        mModulePath(aModulePath),
+        mDebugName(aDebugName),
+        mDebugPath(aDebugPath),
+        mVersion(aVersion),
+        mArch(aArch) {}
+
+  bool operator==(const SharedLibrary& other) const {
+    return (mStart == other.mStart) && (mEnd == other.mEnd) &&
+           (mOffset == other.mOffset) && (mModuleName == other.mModuleName) &&
+           (mModulePath == other.mModulePath) &&
+           (mDebugName == other.mDebugName) &&
+           (mDebugPath == other.mDebugPath) &&
+           (mBreakpadId == other.mBreakpadId) && (mCodeId == other.mCodeId) &&
+           (mVersion == other.mVersion) && (mArch == other.mArch);
+  }
+
+  uintptr_t GetStart() const { return mStart; }
+  uintptr_t GetEnd() const { return mEnd; }
+  uintptr_t GetOffset() const { return mOffset; }
+  const nsCString& GetBreakpadId() const { return mBreakpadId; }
+  const nsCString& GetCodeId() const { return mCodeId; }
+  const nsString& GetModuleName() const { return mModuleName; }
+  const nsString& GetModulePath() const { return mModulePath; }
+  const std::string GetNativeDebugPath() const {
+    nsAutoCString debugPathStr;
+
+    NS_CopyUnicodeToNative(mDebugPath, debugPathStr);
+
+    return debugPathStr.get();
+  }
+  const nsString& GetDebugName() const { return mDebugName; }
+  const nsString& GetDebugPath() const { return mDebugPath; }
+  const nsCString& GetVersion() const { return mVersion; }
+  const std::string& GetArch() const { return mArch; }
+  size_t SizeOf() const {
+    return sizeof *this + mBreakpadId.Length() + mCodeId.Length() +
+           mModuleName.Length() * 2 + mModulePath.Length() * 2 +
+           mDebugName.Length() * 2 + mDebugPath.Length() * 2 +
+           mVersion.Length() + mArch.size();
+  }
+
+  SharedLibrary() : mStart{0}, mEnd{0}, mOffset{0} {}
+
+ private:
+  uintptr_t mStart;
+  uintptr_t mEnd;
+  uintptr_t mOffset;
+  nsCString mBreakpadId;
+  // A string carrying an identifier for a binary.
+  //
+  // All platforms have different formats:
+  // - Windows: The code ID for a Windows PE file.
+  //  It's the PE timestamp and PE image size.
+  // - macOS: The code ID for a macOS / iOS binary (mach-O).
+  //  It's the mach-O UUID without dashes and without the trailing 0 for the
+  //  breakpad ID.
+  // - Linux/Android: The code ID for a Linux ELF file.
+  //  It's the complete build ID, as hex string.
+  nsCString mCodeId;
+  nsString mModuleName;
+  nsString mModulePath;
+  nsString mDebugName;
+  nsString mDebugPath;
+  nsCString mVersion;
+  std::string mArch;
+
+  friend struct IPC::ParamTraits<SharedLibrary>;
+};
+
+static bool CompareAddresses(const SharedLibrary& first,
+                             const SharedLibrary& second) {
+  return first.GetStart() < second.GetStart();
+}
+
+class SharedLibraryInfo {
+ public:
+  static SharedLibraryInfo GetInfoForSelf();
+#ifdef XP_WIN
+  static SharedLibraryInfo GetInfoFromPath(const wchar_t* aPath);
+#endif
+
+  static void Initialize();
+
+  void AddSharedLibrary(SharedLibrary entry) { mEntries.push_back(entry); }
+
+  void AddAllSharedLibraries(const SharedLibraryInfo& sharedLibraryInfo) {
+    mEntries.insert(mEntries.end(), sharedLibraryInfo.mEntries.begin(),
+                    sharedLibraryInfo.mEntries.end());
+  }
+
+  const SharedLibrary& GetEntry(size_t i) const { return mEntries[i]; }
+
+  SharedLibrary& GetMutableEntry(size_t i) { return mEntries[i]; }
+
+  // Removes items in the range [first, last)
+  // i.e. element at the "last" index is not removed
+  void RemoveEntries(size_t first, size_t last) {
+    mEntries.erase(mEntries.begin() + first, mEntries.begin() + last);
+  }
+
+  bool Contains(const SharedLibrary& searchItem) const {
+    return (mEntries.end() !=
+            std::find(mEntries.begin(), mEntries.end(), searchItem));
+  }
+
+  size_t GetSize() const { return mEntries.size(); }
+
+  void SortByAddress() {
+    std::sort(mEntries.begin(), mEntries.end(), CompareAddresses);
+  }
+
+  // Remove duplicate entries from the vector.
+  //
+  // We purposefully don't use the operator== implementation of SharedLibrary
+  // because it compares all the fields including mStart, mEnd and mOffset which
+  // are not the same across different processes.
+  void DeduplicateEntries() {
+    static auto cmpSort = [](const SharedLibrary& a, const SharedLibrary& b) {
+      return std::tie(a.GetModuleName(), a.GetBreakpadId()) <
+             std::tie(b.GetModuleName(), b.GetBreakpadId());
+    };
+    static auto cmpEqual = [](const SharedLibrary& a, const SharedLibrary& b) {
+      return std::tie(a.GetModuleName(), a.GetBreakpadId()) ==
+             std::tie(b.GetModuleName(), b.GetBreakpadId());
+    };
+    // std::unique requires the vector to be sorted first. It can only remove
+    // consecutive duplicate elements.
+    std::sort(mEntries.begin(), mEntries.end(), cmpSort);
+    // Remove the duplicates since it's sorted now.
+    mEntries.erase(std::unique(mEntries.begin(), mEntries.end(), cmpEqual),
+                   mEntries.end());
+  }
+
+  void Clear() { mEntries.clear(); }
+
+  size_t SizeOf() const {
+    size_t size = 0;
+
+    for (const auto& item : mEntries) {
+      size += item.SizeOf();
+    }
+
+    return size;
+  }
+
+ private:
+  std::vector<SharedLibrary> mEntries;
+
+  friend struct IPC::ParamTraits<SharedLibraryInfo>;
+};
+
+namespace IPC {
+template <>
+struct ParamTraits<SharedLibrary> {
+  typedef SharedLibrary paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam);
+  static bool Read(MessageReader* aReader, paramType* aResult);
+};
+
+template <>
+struct ParamTraits<SharedLibraryInfo> {
+  typedef SharedLibraryInfo paramType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam);
+  static bool Read(MessageReader* aReader, paramType* aResult);
+};
+}  // namespace IPC
+
+#endif