Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

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

1 files changed, 1796 insertions, 0 deletions

diff --git a/gfx/webrender_bindings/WebRenderAPI.cpp b/gfx/webrender_bindings/WebRenderAPI.cpp
new file mode 100644
index 0000000000..c07ef299d2
--- /dev/null
+++ b/gfx/webrender_bindings/WebRenderAPI.cpp
@@ -0,0 +1,1796 @@
+/* -*- 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/. */
+
+#include "WebRenderAPI.h"
+
+#include "mozilla/ipc/ByteBuf.h"
+#include "mozilla/webrender/RendererOGL.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/layers/CompositorThread.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/StaticPrefs_webgl.h"
+#include "mozilla/ToString.h"
+#include "mozilla/webrender/RenderCompositor.h"
+#include "mozilla/widget/CompositorWidget.h"
+#include "mozilla/layers/SynchronousTask.h"
+#include "nsThreadUtils.h"
+#include "TextDrawTarget.h"
+#include "malloc_decls.h"
+#include "GLContext.h"
+
+// clang-format off
+#define WRDL_LOG(...)
+//#define WRDL_LOG(...) printf_stderr("WRDL(%p): " __VA_ARGS__)
+//#define WRDL_LOG(...) if (XRE_IsContentProcess()) printf_stderr("WRDL(%p): " __VA_ARGS__)
+// clang-format on
+
+namespace mozilla {
+using namespace layers;
+
+namespace wr {
+
+MOZ_DEFINE_MALLOC_SIZE_OF(WebRenderMallocSizeOf)
+MOZ_DEFINE_MALLOC_ENCLOSING_SIZE_OF(WebRenderMallocEnclosingSizeOf)
+
+class NewRenderer : public RendererEvent {
+ public:
+  NewRenderer(wr::DocumentHandle** aDocHandle,
+              layers::CompositorBridgeParent* aBridge,
+              WebRenderBackend* aBackend, WebRenderCompositor* aCompositor,
+              int32_t* aMaxTextureSize, bool* aUseANGLE, bool* aUseDComp,
+              bool* aUseTripleBuffering, bool* aSupportsExternalBufferTextures,
+              RefPtr<widget::CompositorWidget>&& aWidget,
+              layers::SynchronousTask* aTask, LayoutDeviceIntSize aSize,
+              layers::WindowKind aWindowKind, layers::SyncHandle* aHandle,
+              nsACString* aError)
+      : mDocHandle(aDocHandle),
+        mBackend(aBackend),
+        mCompositor(aCompositor),
+        mMaxTextureSize(aMaxTextureSize),
+        mUseANGLE(aUseANGLE),
+        mUseDComp(aUseDComp),
+        mUseTripleBuffering(aUseTripleBuffering),
+        mSupportsExternalBufferTextures(aSupportsExternalBufferTextures),
+        mBridge(aBridge),
+        mCompositorWidget(std::move(aWidget)),
+        mTask(aTask),
+        mSize(aSize),
+        mWindowKind(aWindowKind),
+        mSyncHandle(aHandle),
+        mError(aError) {
+    MOZ_COUNT_CTOR(NewRenderer);
+  }
+
+  MOZ_COUNTED_DTOR(NewRenderer)
+
+  void Run(RenderThread& aRenderThread, WindowId aWindowId) override {
+    layers::AutoCompleteTask complete(mTask);
+
+    UniquePtr<RenderCompositor> compositor =
+        RenderCompositor::Create(std::move(mCompositorWidget), *mError);
+    if (!compositor) {
+      if (!mError->IsEmpty()) {
+        gfxCriticalNote << mError->BeginReading();
+      }
+      return;
+    }
+
+    compositor->MakeCurrent();
+
+    *mBackend = compositor->BackendType();
+    *mCompositor = compositor->CompositorType();
+    *mUseANGLE = compositor->UseANGLE();
+    *mUseDComp = compositor->UseDComp();
+    *mUseTripleBuffering = compositor->UseTripleBuffering();
+    *mSupportsExternalBufferTextures =
+        compositor->SupportsExternalBufferTextures();
+
+    // Only allow the panic on GL error functionality in nightly builds,
+    // since it (deliberately) crashes the GPU process if any GL call
+    // returns an error code.
+    bool panic_on_gl_error = false;
+#ifdef NIGHTLY_BUILD
+    panic_on_gl_error =
+        StaticPrefs::gfx_webrender_panic_on_gl_error_AtStartup();
+#endif
+
+    bool isMainWindow = true;  // TODO!
+    bool supportLowPriorityTransactions = isMainWindow;
+    bool supportLowPriorityThreadpool =
+        supportLowPriorityTransactions &&
+        StaticPrefs::gfx_webrender_enable_low_priority_pool();
+    wr::Renderer* wrRenderer = nullptr;
+    char* errorMessage = nullptr;
+    int picTileWidth = StaticPrefs::gfx_webrender_picture_tile_width();
+    int picTileHeight = StaticPrefs::gfx_webrender_picture_tile_height();
+    auto* swgl = compositor->swgl();
+    auto* gl = (compositor->gl() && !swgl) ? compositor->gl() : nullptr;
+    auto* progCache = (aRenderThread.GetProgramCache() && !swgl)
+                          ? aRenderThread.GetProgramCache()->Raw()
+                          : nullptr;
+    auto* shaders = (aRenderThread.GetShaders() && !swgl)
+                        ? aRenderThread.GetShaders()->RawShaders()
+                        : nullptr;
+
+    // Check That if we are not using SWGL, we have at least a GL or GLES 3.0
+    // context.
+    if (gl && !swgl) {
+      bool versionCheck =
+          gl->IsAtLeast(gl::ContextProfile::OpenGLCore, 300) ||
+          gl->IsAtLeast(gl::ContextProfile::OpenGLCompatibility, 300) ||
+          gl->IsAtLeast(gl::ContextProfile::OpenGLES, 300);
+
+      if (!versionCheck) {
+        gfxCriticalNote << "GL context version (" << gl->Version()
+                        << ") insufficent for hardware WebRender";
+
+        mError->AssignASCII("GL context version insufficient");
+        return;
+      }
+    }
+
+    if (!wr_window_new(
+            aWindowId, mSize.width, mSize.height,
+            mWindowKind == WindowKind::MAIN, supportLowPriorityTransactions,
+            supportLowPriorityThreadpool, gfx::gfxVars::UseGLSwizzle(),
+            gfx::gfxVars::UseWebRenderScissoredCacheClears(), swgl, gl,
+            compositor->SurfaceOriginIsTopLeft(), progCache, shaders,
+            aRenderThread.ThreadPool().Raw(),
+            aRenderThread.ThreadPoolLP().Raw(), &WebRenderMallocSizeOf,
+            &WebRenderMallocEnclosingSizeOf, 0, compositor.get(),
+            compositor->ShouldUseNativeCompositor(),
+            compositor->UsePartialPresent(),
+            compositor->GetMaxPartialPresentRects(),
+            compositor->ShouldDrawPreviousPartialPresentRegions(), mDocHandle,
+            &wrRenderer, mMaxTextureSize, &errorMessage,
+            StaticPrefs::gfx_webrender_enable_gpu_markers_AtStartup(),
+            panic_on_gl_error, picTileWidth, picTileHeight,
+            gfx::gfxVars::WebRenderRequiresHardwareDriver(),
+            StaticPrefs::gfx_webrender_low_quality_pinch_zoom_AtStartup(),
+            StaticPrefs::gfx_webrender_max_shared_surface_size_AtStartup())) {
+      // wr_window_new puts a message into gfxCriticalNote if it returns false
+      MOZ_ASSERT(errorMessage);
+      mError->AssignASCII(errorMessage);
+      wr_api_free_error_msg(errorMessage);
+      return;
+    }
+    MOZ_ASSERT(wrRenderer);
+
+    RefPtr<RenderThread> thread = &aRenderThread;
+    auto renderer =
+        MakeUnique<RendererOGL>(std::move(thread), std::move(compositor),
+                                aWindowId, wrRenderer, mBridge);
+    if (wrRenderer && renderer) {
+      wr::WrExternalImageHandler handler = renderer->GetExternalImageHandler();
+      wr_renderer_set_external_image_handler(wrRenderer, &handler);
+    }
+
+    if (renderer) {
+      layers::SyncObjectHost* syncObj = renderer->GetSyncObject();
+      if (syncObj) {
+        *mSyncHandle = syncObj->GetSyncHandle();
+      }
+    }
+
+    aRenderThread.AddRenderer(aWindowId, std::move(renderer));
+  }
+
+ private:
+  wr::DocumentHandle** mDocHandle;
+  WebRenderBackend* mBackend;
+  WebRenderCompositor* mCompositor;
+  int32_t* mMaxTextureSize;
+  bool* mUseANGLE;
+  bool* mUseDComp;
+  bool* mUseTripleBuffering;
+  bool* mSupportsExternalBufferTextures;
+  layers::CompositorBridgeParent* mBridge;
+  RefPtr<widget::CompositorWidget> mCompositorWidget;
+  layers::SynchronousTask* mTask;
+  LayoutDeviceIntSize mSize;
+  layers::WindowKind mWindowKind;
+  layers::SyncHandle* mSyncHandle;
+  nsACString* mError;
+};
+
+class RemoveRenderer : public RendererEvent {
+ public:
+  explicit RemoveRenderer(layers::SynchronousTask* aTask) : mTask(aTask) {
+    MOZ_COUNT_CTOR(RemoveRenderer);
+  }
+
+  MOZ_COUNTED_DTOR_OVERRIDE(RemoveRenderer)
+
+  void Run(RenderThread& aRenderThread, WindowId aWindowId) override {
+    aRenderThread.RemoveRenderer(aWindowId);
+    layers::AutoCompleteTask complete(mTask);
+  }
+
+ private:
+  layers::SynchronousTask* mTask;
+};
+
+TransactionBuilder::TransactionBuilder(WebRenderAPI* aApi,
+                                       bool aUseSceneBuilderThread)
+    : mUseSceneBuilderThread(aUseSceneBuilderThread),
+      mApiBackend(aApi->GetBackendType()) {
+  mTxn = wr_transaction_new(mUseSceneBuilderThread);
+}
+
+TransactionBuilder::~TransactionBuilder() { wr_transaction_delete(mTxn); }
+
+void TransactionBuilder::SetLowPriority(bool aIsLowPriority) {
+  wr_transaction_set_low_priority(mTxn, aIsLowPriority);
+}
+
+void TransactionBuilder::UpdateEpoch(PipelineId aPipelineId, Epoch aEpoch) {
+  wr_transaction_update_epoch(mTxn, aPipelineId, aEpoch);
+}
+
+void TransactionBuilder::SetRootPipeline(PipelineId aPipelineId) {
+  wr_transaction_set_root_pipeline(mTxn, aPipelineId);
+}
+
+void TransactionBuilder::RemovePipeline(PipelineId aPipelineId) {
+  wr_transaction_remove_pipeline(mTxn, aPipelineId);
+}
+
+void TransactionBuilder::SetDisplayList(
+    Epoch aEpoch, wr::WrPipelineId pipeline_id,
+    wr::BuiltDisplayListDescriptor dl_descriptor,
+    wr::Vec<uint8_t>& dl_items_data, wr::Vec<uint8_t>& dl_cache_data,
+    wr::Vec<uint8_t>& dl_spatial_tree) {
+  wr_transaction_set_display_list(mTxn, aEpoch, pipeline_id, dl_descriptor,
+                                  &dl_items_data.inner, &dl_cache_data.inner,
+                                  &dl_spatial_tree.inner);
+}
+
+void TransactionBuilder::ClearDisplayList(Epoch aEpoch,
+                                          wr::WrPipelineId aPipelineId) {
+  wr_transaction_clear_display_list(mTxn, aEpoch, aPipelineId);
+}
+
+void TransactionBuilder::GenerateFrame(const VsyncId& aVsyncId,
+                                       wr::RenderReasons aReasons) {
+  wr_transaction_generate_frame(mTxn, aVsyncId.mId, aReasons);
+}
+
+void TransactionBuilder::InvalidateRenderedFrame(wr::RenderReasons aReasons) {
+  wr_transaction_invalidate_rendered_frame(mTxn, aReasons);
+}
+
+bool TransactionBuilder::IsEmpty() const {
+  return wr_transaction_is_empty(mTxn);
+}
+
+bool TransactionBuilder::IsResourceUpdatesEmpty() const {
+  return wr_transaction_resource_updates_is_empty(mTxn);
+}
+
+bool TransactionBuilder::IsRenderedFrameInvalidated() const {
+  return wr_transaction_is_rendered_frame_invalidated(mTxn);
+}
+
+void TransactionBuilder::SetDocumentView(
+    const LayoutDeviceIntRect& aDocumentRect) {
+  wr::DeviceIntRect wrDocRect;
+  wrDocRect.min.x = aDocumentRect.x;
+  wrDocRect.min.y = aDocumentRect.y;
+  wrDocRect.max.x = aDocumentRect.x + aDocumentRect.width;
+  wrDocRect.max.y = aDocumentRect.y + aDocumentRect.height;
+  wr_transaction_set_document_view(mTxn, &wrDocRect);
+}
+
+TransactionWrapper::TransactionWrapper(Transaction* aTxn) : mTxn(aTxn) {}
+
+void TransactionWrapper::AppendDynamicProperties(
+    const nsTArray<wr::WrOpacityProperty>& aOpacityArray,
+    const nsTArray<wr::WrTransformProperty>& aTransformArray,
+    const nsTArray<wr::WrColorProperty>& aColorArray) {
+  wr_transaction_append_dynamic_properties(
+      mTxn, aOpacityArray.IsEmpty() ? nullptr : aOpacityArray.Elements(),
+      aOpacityArray.Length(),
+      aTransformArray.IsEmpty() ? nullptr : aTransformArray.Elements(),
+      aTransformArray.Length(),
+      aColorArray.IsEmpty() ? nullptr : aColorArray.Elements(),
+      aColorArray.Length());
+}
+
+void TransactionWrapper::AppendTransformProperties(
+    const nsTArray<wr::WrTransformProperty>& aTransformArray) {
+  wr_transaction_append_transform_properties(
+      mTxn, aTransformArray.IsEmpty() ? nullptr : aTransformArray.Elements(),
+      aTransformArray.Length());
+}
+
+void TransactionWrapper::UpdateScrollPosition(
+    const wr::WrPipelineId& aPipelineId,
+    const layers::ScrollableLayerGuid::ViewID& aScrollId,
+    const nsTArray<wr::SampledScrollOffset>& aSampledOffsets) {
+  wr_transaction_scroll_layer(mTxn, aPipelineId, aScrollId, &aSampledOffsets);
+}
+
+void TransactionWrapper::UpdateIsTransformAsyncZooming(uint64_t aAnimationId,
+                                                       bool aIsZooming) {
+  wr_transaction_set_is_transform_async_zooming(mTxn, aAnimationId, aIsZooming);
+}
+
+/*static*/
+already_AddRefed<WebRenderAPI> WebRenderAPI::Create(
+    layers::CompositorBridgeParent* aBridge,
+    RefPtr<widget::CompositorWidget>&& aWidget, const wr::WrWindowId& aWindowId,
+    LayoutDeviceIntSize aSize, layers::WindowKind aWindowKind,
+    nsACString& aError) {
+  MOZ_ASSERT(aBridge);
+  MOZ_ASSERT(aWidget);
+  static_assert(
+      sizeof(size_t) == sizeof(uintptr_t),
+      "The FFI bindings assume size_t is the same size as uintptr_t!");
+
+  wr::DocumentHandle* docHandle = nullptr;
+  WebRenderBackend backend = WebRenderBackend::HARDWARE;
+  WebRenderCompositor compositor = WebRenderCompositor::DRAW;
+  int32_t maxTextureSize = 0;
+  bool useANGLE = false;
+  bool useDComp = false;
+  bool useTripleBuffering = false;
+  bool supportsExternalBufferTextures = false;
+  layers::SyncHandle syncHandle = 0;
+
+  // Dispatch a synchronous task because the DocumentHandle object needs to be
+  // created on the render thread. If need be we could delay waiting on this
+  // task until the next time we need to access the DocumentHandle object.
+  layers::SynchronousTask task("Create Renderer");
+  auto event = MakeUnique<NewRenderer>(
+      &docHandle, aBridge, &backend, &compositor, &maxTextureSize, &useANGLE,
+      &useDComp, &useTripleBuffering, &supportsExternalBufferTextures,
+      std::move(aWidget), &task, aSize, aWindowKind, &syncHandle, &aError);
+  RenderThread::Get()->PostEvent(aWindowId, std::move(event));
+
+  task.Wait();
+
+  if (!docHandle) {
+    return nullptr;
+  }
+
+  return RefPtr<WebRenderAPI>(
+             new WebRenderAPI(docHandle, aWindowId, backend, compositor,
+                              maxTextureSize, useANGLE, useDComp,
+                              useTripleBuffering,
+                              supportsExternalBufferTextures, syncHandle))
+      .forget();
+}
+
+already_AddRefed<WebRenderAPI> WebRenderAPI::Clone() {
+  wr::DocumentHandle* docHandle = nullptr;
+  wr_api_clone(mDocHandle, &docHandle);
+
+  RefPtr<WebRenderAPI> renderApi =
+      new WebRenderAPI(docHandle, mId, mBackend, mCompositor, mMaxTextureSize,
+                       mUseANGLE, mUseDComp, mUseTripleBuffering,
+                       mSupportsExternalBufferTextures, mSyncHandle);
+  renderApi->mRootApi = this;  // Hold root api
+  renderApi->mRootDocumentApi = this;
+
+  return renderApi.forget();
+}
+
+wr::WrIdNamespace WebRenderAPI::GetNamespace() {
+  return wr_api_get_namespace(mDocHandle);
+}
+
+WebRenderAPI::WebRenderAPI(wr::DocumentHandle* aHandle, wr::WindowId aId,
+                           WebRenderBackend aBackend,
+                           WebRenderCompositor aCompositor,
+                           uint32_t aMaxTextureSize, bool aUseANGLE,
+                           bool aUseDComp, bool aUseTripleBuffering,
+                           bool aSupportsExternalBufferTextures,
+                           layers::SyncHandle aSyncHandle)
+    : mDocHandle(aHandle),
+      mId(aId),
+      mBackend(aBackend),
+      mCompositor(aCompositor),
+      mMaxTextureSize(aMaxTextureSize),
+      mUseANGLE(aUseANGLE),
+      mUseDComp(aUseDComp),
+      mUseTripleBuffering(aUseTripleBuffering),
+      mSupportsExternalBufferTextures(aSupportsExternalBufferTextures),
+      mCaptureSequence(false),
+      mSyncHandle(aSyncHandle),
+      mRendererDestroyed(false) {}
+
+WebRenderAPI::~WebRenderAPI() {
+  if (!mRootDocumentApi) {
+    wr_api_delete_document(mDocHandle);
+  }
+
+  if (!mRootApi) {
+    MOZ_RELEASE_ASSERT(mRendererDestroyed);
+    wr_api_shut_down(mDocHandle);
+  }
+
+  wr_api_delete(mDocHandle);
+}
+
+void WebRenderAPI::DestroyRenderer() {
+  MOZ_RELEASE_ASSERT(!mRootApi);
+
+  RenderThread::Get()->SetDestroyed(GetId());
+  // Call wr_api_stop_render_backend() before RemoveRenderer.
+  wr_api_stop_render_backend(mDocHandle);
+
+  layers::SynchronousTask task("Destroy WebRenderAPI");
+  auto event = MakeUnique<RemoveRenderer>(&task);
+  RunOnRenderThread(std::move(event));
+  task.Wait();
+
+  mRendererDestroyed = true;
+}
+
+void WebRenderAPI::UpdateDebugFlags(uint32_t aFlags) {
+  wr_api_set_debug_flags(mDocHandle, wr::DebugFlags{aFlags});
+}
+
+void WebRenderAPI::SendTransaction(TransactionBuilder& aTxn) {
+  if (mRootApi && mRootApi->mRendererDestroyed) {
+    return;
+  }
+
+  if (mPendingRemoteTextureInfoList &&
+      !mPendingRemoteTextureInfoList->mList.empty()) {
+    mPendingWrTransactionEvents.emplace(
+        WrTransactionEvent::PendingRemoteTextures(
+            std::move(mPendingRemoteTextureInfoList)));
+  }
+
+  if (!mPendingWrTransactionEvents.empty()) {
+    mPendingWrTransactionEvents.emplace(WrTransactionEvent::Transaction(
+        aTxn.Take(), aTxn.UseSceneBuilderThread()));
+    HandleWrTransactionEvents(RemoteTextureWaitType::AsyncWait);
+  } else {
+    wr_api_send_transaction(mDocHandle, aTxn.Raw(),
+                            aTxn.UseSceneBuilderThread());
+  }
+}
+
+layers::RemoteTextureInfoList* WebRenderAPI::GetPendingRemoteTextureInfoList() {
+  if (!mRootApi) {
+    // root api does not support async wait RemoteTexture.
+    return nullptr;
+  }
+
+  if (!gfx::gfxVars::UseCanvasRenderThread() ||
+      !StaticPrefs::webgl_out_of_process_async_present() ||
+      gfx::gfxVars::WebglOopAsyncPresentForceSync()) {
+    return nullptr;
+  }
+
+  // async remote texture is enabled
+  MOZ_ASSERT(gfx::gfxVars::UseCanvasRenderThread());
+  MOZ_ASSERT(StaticPrefs::webgl_out_of_process_async_present());
+  MOZ_ASSERT(!gfx::gfxVars::WebglOopAsyncPresentForceSync());
+
+  if (!mPendingRemoteTextureInfoList) {
+    mPendingRemoteTextureInfoList = MakeUnique<layers::RemoteTextureInfoList>();
+  }
+  return mPendingRemoteTextureInfoList.get();
+}
+
+bool WebRenderAPI::CheckIsRemoteTextureReady(
+    layers::RemoteTextureInfoList* aList) {
+  MOZ_ASSERT(layers::CompositorThreadHolder::IsInCompositorThread());
+  MOZ_ASSERT(aList);
+  MOZ_ASSERT(gfx::gfxVars::UseCanvasRenderThread());
+  MOZ_ASSERT(StaticPrefs::webgl_out_of_process_async_present());
+  MOZ_ASSERT(!gfx::gfxVars::WebglOopAsyncPresentForceSync());
+
+  RefPtr<WebRenderAPI> self = this;
+  auto callback = [self](const layers::RemoteTextureInfo&) {
+    RefPtr<nsIRunnable> runnable = NewRunnableMethod<RemoteTextureWaitType>(
+        "WebRenderAPI::HandleWrTransactionEvents", self,
+        &WebRenderAPI::HandleWrTransactionEvents,
+        RemoteTextureWaitType::AsyncWait);
+    layers::CompositorThread()->Dispatch(runnable.forget());
+  };
+
+  bool isReady = true;
+  while (!aList->mList.empty() && isReady) {
+    auto& front = aList->mList.front();
+    isReady &= layers::RemoteTextureMap::Get()->CheckRemoteTextureReady(
+        front, callback);
+    if (isReady) {
+      aList->mList.pop();
+    }
+  }
+
+  return isReady;
+}
+
+void WebRenderAPI::WaitRemoteTextureReady(
+    layers::RemoteTextureInfoList* aList) {
+  MOZ_ASSERT(layers::CompositorThreadHolder::IsInCompositorThread());
+  MOZ_ASSERT(aList);
+  MOZ_ASSERT(gfx::gfxVars::UseCanvasRenderThread());
+  MOZ_ASSERT(StaticPrefs::webgl_out_of_process_async_present());
+  MOZ_ASSERT(!gfx::gfxVars::WebglOopAsyncPresentForceSync());
+
+  while (!aList->mList.empty()) {
+    auto& front = aList->mList.front();
+    layers::RemoteTextureMap::Get()->WaitRemoteTextureReady(front);
+    aList->mList.pop();
+  }
+}
+
+void WebRenderAPI::FlushPendingWrTransactionEventsWithoutWait() {
+  HandleWrTransactionEvents(RemoteTextureWaitType::FlushWithoutWait);
+}
+
+void WebRenderAPI::FlushPendingWrTransactionEventsWithWait() {
+  HandleWrTransactionEvents(RemoteTextureWaitType::FlushWithWait);
+}
+
+void WebRenderAPI::HandleWrTransactionEvents(RemoteTextureWaitType aType) {
+  auto& events = mPendingWrTransactionEvents;
+
+  while (!events.empty()) {
+    auto& front = events.front();
+    switch (front.mTag) {
+      case WrTransactionEvent::Tag::Transaction:
+        wr_api_send_transaction(mDocHandle, front.Transaction(),
+                                front.UseSceneBuilderThread());
+        break;
+      case WrTransactionEvent::Tag::PendingRemoteTextures:
+        bool isReady = true;
+        if (aType == RemoteTextureWaitType::AsyncWait) {
+          isReady = CheckIsRemoteTextureReady(front.RemoteTextureInfoList());
+        } else if (aType == RemoteTextureWaitType::FlushWithWait) {
+          WaitRemoteTextureReady(front.RemoteTextureInfoList());
+        } else {
+          MOZ_ASSERT(aType == RemoteTextureWaitType::FlushWithoutWait);
+          auto* list = front.RemoteTextureInfoList();
+          while (!list->mList.empty()) {
+            auto& front = list->mList.front();
+            layers::RemoteTextureMap::Get()->SuppressRemoteTextureReadyCheck(
+                front.mTextureId, front.mForPid);
+            list->mList.pop();
+          }
+        }
+        if (!isReady) {
+          return;
+        }
+        break;
+    }
+    events.pop();
+  }
+}
+
+std::vector<WrHitResult> WebRenderAPI::HitTest(const wr::WorldPoint& aPoint) {
+  static_assert(gfx::DoesCompositorHitTestInfoFitIntoBits<12>(),
+                "CompositorHitTestFlags MAX value has to be less than number "
+                "of bits in uint16_t minus 4 for SideBitsPacked");
+
+  nsTArray<wr::HitResult> wrResults;
+  wr_api_hit_test(mDocHandle, aPoint, &wrResults);
+
+  std::vector<WrHitResult> geckoResults;
+  for (wr::HitResult wrResult : wrResults) {
+    WrHitResult geckoResult;
+    geckoResult.mLayersId = wr::AsLayersId(wrResult.pipeline_id);
+    geckoResult.mScrollId =
+        static_cast<layers::ScrollableLayerGuid::ViewID>(wrResult.scroll_id);
+    geckoResult.mHitInfo.deserialize(wrResult.hit_info & 0x0fff);
+    geckoResult.mSideBits = static_cast<SideBits>(wrResult.hit_info >> 12);
+
+    if (wrResult.animation_id != 0) {
+      geckoResult.mAnimationId = Some(wrResult.animation_id);
+    } else {
+      geckoResult.mAnimationId = Nothing();
+    }
+    geckoResults.push_back(geckoResult);
+  }
+  return geckoResults;
+}
+
+void WebRenderAPI::Readback(const TimeStamp& aStartTime, gfx::IntSize size,
+                            const gfx::SurfaceFormat& aFormat,
+                            const Range<uint8_t>& buffer, bool* aNeedsYFlip) {
+  class Readback : public RendererEvent {
+   public:
+    explicit Readback(layers::SynchronousTask* aTask, TimeStamp aStartTime,
+                      gfx::IntSize aSize, const gfx::SurfaceFormat& aFormat,
+                      const Range<uint8_t>& aBuffer, bool* aNeedsYFlip)
+        : mTask(aTask),
+          mStartTime(aStartTime),
+          mSize(aSize),
+          mFormat(aFormat),
+          mBuffer(aBuffer),
+          mNeedsYFlip(aNeedsYFlip) {
+      MOZ_COUNT_CTOR(Readback);
+    }
+
+    MOZ_COUNTED_DTOR_OVERRIDE(Readback)
+
+    void Run(RenderThread& aRenderThread, WindowId aWindowId) override {
+      aRenderThread.UpdateAndRender(aWindowId, VsyncId(), mStartTime,
+                                    /* aRender */ true, Some(mSize),
+                                    wr::SurfaceFormatToImageFormat(mFormat),
+                                    Some(mBuffer), mNeedsYFlip);
+      layers::AutoCompleteTask complete(mTask);
+    }
+
+    layers::SynchronousTask* mTask;
+    TimeStamp mStartTime;
+    gfx::IntSize mSize;
+    gfx::SurfaceFormat mFormat;
+    const Range<uint8_t>& mBuffer;
+    bool* mNeedsYFlip;
+  };
+
+  // Disable debug flags during readback. See bug 1436020.
+  UpdateDebugFlags(0);
+
+  layers::SynchronousTask task("Readback");
+  auto event = MakeUnique<Readback>(&task, aStartTime, size, aFormat, buffer,
+                                    aNeedsYFlip);
+  // This event will be passed from wr_backend thread to renderer thread. That
+  // implies that all frame data have been processed when the renderer runs this
+  // read-back event. Then, we could make sure this read-back event gets the
+  // latest result.
+  RunOnRenderThread(std::move(event));
+
+  task.Wait();
+
+  UpdateDebugFlags(gfx::gfxVars::WebRenderDebugFlags());
+}
+
+void WebRenderAPI::ClearAllCaches() { wr_api_clear_all_caches(mDocHandle); }
+
+void WebRenderAPI::EnableNativeCompositor(bool aEnable) {
+  wr_api_enable_native_compositor(mDocHandle, aEnable);
+}
+
+void WebRenderAPI::SetBatchingLookback(uint32_t aCount) {
+  wr_api_set_batching_lookback(mDocHandle, aCount);
+}
+
+void WebRenderAPI::SetBool(wr::BoolParameter aKey, bool aValue) {
+  wr_api_set_bool(mDocHandle, aKey, aValue);
+}
+
+void WebRenderAPI::SetInt(wr::IntParameter aKey, int32_t aValue) {
+  wr_api_set_int(mDocHandle, aKey, aValue);
+}
+
+void WebRenderAPI::SetClearColor(const gfx::DeviceColor& aColor) {
+  RenderThread::Get()->SetClearColor(mId, ToColorF(aColor));
+}
+
+void WebRenderAPI::SetProfilerUI(const nsACString& aUIString) {
+  RenderThread::Get()->SetProfilerUI(mId, aUIString);
+}
+
+void WebRenderAPI::Pause() {
+  class PauseEvent : public RendererEvent {
+   public:
+    explicit PauseEvent(layers::SynchronousTask* aTask) : mTask(aTask) {
+      MOZ_COUNT_CTOR(PauseEvent);
+    }
+
+    MOZ_COUNTED_DTOR_OVERRIDE(PauseEvent)
+
+    void Run(RenderThread& aRenderThread, WindowId aWindowId) override {
+      aRenderThread.Pause(aWindowId);
+      layers::AutoCompleteTask complete(mTask);
+    }
+
+    layers::SynchronousTask* mTask;
+  };
+
+  layers::SynchronousTask task("Pause");
+  auto event = MakeUnique<PauseEvent>(&task);
+  // This event will be passed from wr_backend thread to renderer thread. That
+  // implies that all frame data have been processed when the renderer runs this
+  // event.
+  RunOnRenderThread(std::move(event));
+
+  task.Wait();
+}
+
+bool WebRenderAPI::Resume() {
+  class ResumeEvent : public RendererEvent {
+   public:
+    explicit ResumeEvent(layers::SynchronousTask* aTask, bool* aResult)
+        : mTask(aTask), mResult(aResult) {
+      MOZ_COUNT_CTOR(ResumeEvent);
+    }
+
+    MOZ_COUNTED_DTOR_OVERRIDE(ResumeEvent)
+
+    void Run(RenderThread& aRenderThread, WindowId aWindowId) override {
+      *mResult = aRenderThread.Resume(aWindowId);
+      layers::AutoCompleteTask complete(mTask);
+    }
+
+    layers::SynchronousTask* mTask;
+    bool* mResult;
+  };
+
+  bool result = false;
+  layers::SynchronousTask task("Resume");
+  auto event = MakeUnique<ResumeEvent>(&task, &result);
+  // This event will be passed from wr_backend thread to renderer thread. That
+  // implies that all frame data have been processed when the renderer runs this
+  // event.
+  RunOnRenderThread(std::move(event));
+
+  task.Wait();
+  return result;
+}
+
+void WebRenderAPI::NotifyMemoryPressure() {
+  wr_api_notify_memory_pressure(mDocHandle);
+}
+
+void WebRenderAPI::AccumulateMemoryReport(MemoryReport* aReport) {
+  wr_api_accumulate_memory_report(mDocHandle, aReport, &WebRenderMallocSizeOf,
+                                  &WebRenderMallocEnclosingSizeOf);
+}
+
+void WebRenderAPI::WakeSceneBuilder() { wr_api_wake_scene_builder(mDocHandle); }
+
+void WebRenderAPI::FlushSceneBuilder() {
+  wr_api_flush_scene_builder(mDocHandle);
+}
+
+void WebRenderAPI::WaitFlushed() {
+  class WaitFlushedEvent : public RendererEvent {
+   public:
+    explicit WaitFlushedEvent(layers::SynchronousTask* aTask) : mTask(aTask) {
+      MOZ_COUNT_CTOR(WaitFlushedEvent);
+    }
+
+    MOZ_COUNTED_DTOR_OVERRIDE(WaitFlushedEvent)
+
+    void Run(RenderThread& aRenderThread, WindowId aWindowId) override {
+      layers::AutoCompleteTask complete(mTask);
+    }
+
+    layers::SynchronousTask* mTask;
+  };
+
+  layers::SynchronousTask task("WaitFlushed");
+  auto event = MakeUnique<WaitFlushedEvent>(&task);
+  // This event will be passed from wr_backend thread to renderer thread. That
+  // implies that all frame data have been processed when the renderer runs this
+  // event.
+  RunOnRenderThread(std::move(event));
+
+  task.Wait();
+}
+
+void WebRenderAPI::Capture() {
+  // see CaptureBits
+  // SCENE | FRAME | TILE_CACHE
+  uint8_t bits = 15;                // TODO: get from JavaScript
+  const char* path = "wr-capture";  // TODO: get from JavaScript
+  wr_api_capture(mDocHandle, path, bits);
+}
+
+void WebRenderAPI::StartCaptureSequence(const nsACString& aPath,
+                                        uint32_t aFlags) {
+  if (mCaptureSequence) {
+    wr_api_stop_capture_sequence(mDocHandle);
+  }
+
+  wr_api_start_capture_sequence(mDocHandle, PromiseFlatCString(aPath).get(),
+                                aFlags);
+
+  mCaptureSequence = true;
+}
+
+void WebRenderAPI::StopCaptureSequence() {
+  if (mCaptureSequence) {
+    wr_api_stop_capture_sequence(mDocHandle);
+  }
+
+  mCaptureSequence = false;
+}
+
+void WebRenderAPI::BeginRecording(const TimeStamp& aRecordingStart,
+                                  wr::PipelineId aRootPipelineId) {
+  class BeginRecordingEvent final : public RendererEvent {
+   public:
+    explicit BeginRecordingEvent(const TimeStamp& aRecordingStart,
+                                 wr::PipelineId aRootPipelineId)
+        : mRecordingStart(aRecordingStart), mRootPipelineId(aRootPipelineId) {
+      MOZ_COUNT_CTOR(BeginRecordingEvent);
+    }
+
+    ~BeginRecordingEvent() { MOZ_COUNT_DTOR(BeginRecordingEvent); }
+
+    void Run(RenderThread& aRenderThread, WindowId aWindowId) override {
+      aRenderThread.BeginRecordingForWindow(aWindowId, mRecordingStart,
+                                            mRootPipelineId);
+    }
+
+   private:
+    TimeStamp mRecordingStart;
+    wr::PipelineId mRootPipelineId;
+  };
+
+  auto event =
+      MakeUnique<BeginRecordingEvent>(aRecordingStart, aRootPipelineId);
+  RunOnRenderThread(std::move(event));
+}
+
+RefPtr<WebRenderAPI::EndRecordingPromise> WebRenderAPI::EndRecording() {
+  class EndRecordingEvent final : public RendererEvent {
+   public:
+    explicit EndRecordingEvent() { MOZ_COUNT_CTOR(EndRecordingEvent); }
+
+    MOZ_COUNTED_DTOR(EndRecordingEvent);
+
+    void Run(RenderThread& aRenderThread, WindowId aWindowId) override {
+      Maybe<layers::FrameRecording> recording =
+          aRenderThread.EndRecordingForWindow(aWindowId);
+
+      if (recording) {
+        mPromise.Resolve(recording.extract(), __func__);
+      } else {
+        mPromise.Reject(NS_ERROR_UNEXPECTED, __func__);
+      }
+    }
+
+    RefPtr<WebRenderAPI::EndRecordingPromise> GetPromise() {
+      return mPromise.Ensure(__func__);
+    }
+
+   private:
+    MozPromiseHolder<WebRenderAPI::EndRecordingPromise> mPromise;
+  };
+
+  auto event = MakeUnique<EndRecordingEvent>();
+  auto promise = event->GetPromise();
+
+  RunOnRenderThread(std::move(event));
+  return promise;
+}
+
+void TransactionBuilder::Clear() { wr_resource_updates_clear(mTxn); }
+
+Transaction* TransactionBuilder::Take() {
+  Transaction* txn = mTxn;
+  mTxn = wr_transaction_new(mUseSceneBuilderThread);
+  return txn;
+}
+
+void TransactionBuilder::Notify(wr::Checkpoint aWhen,
+                                UniquePtr<NotificationHandler> aEvent) {
+  wr_transaction_notify(mTxn, aWhen,
+                        reinterpret_cast<uintptr_t>(aEvent.release()));
+}
+
+void TransactionBuilder::AddImage(ImageKey key,
+                                  const ImageDescriptor& aDescriptor,
+                                  wr::Vec<uint8_t>& aBytes) {
+  wr_resource_updates_add_image(mTxn, key, &aDescriptor, &aBytes.inner);
+}
+
+void TransactionBuilder::AddBlobImage(BlobImageKey key,
+                                      const ImageDescriptor& aDescriptor,
+                                      uint16_t aTileSize,
+                                      wr::Vec<uint8_t>& aBytes,
+                                      const wr::DeviceIntRect& aVisibleRect) {
+  wr_resource_updates_add_blob_image(mTxn, key, &aDescriptor, aTileSize,
+                                     &aBytes.inner, aVisibleRect);
+}
+
+void TransactionBuilder::AddExternalImage(ImageKey key,
+                                          const ImageDescriptor& aDescriptor,
+                                          ExternalImageId aExtID,
+                                          wr::ExternalImageType aImageType,
+                                          uint8_t aChannelIndex) {
+  wr_resource_updates_add_external_image(mTxn, key, &aDescriptor, aExtID,
+                                         &aImageType, aChannelIndex);
+}
+
+void TransactionBuilder::AddExternalImageBuffer(
+    ImageKey aKey, const ImageDescriptor& aDescriptor,
+    ExternalImageId aHandle) {
+  auto channelIndex = 0;
+  AddExternalImage(aKey, aDescriptor, aHandle, wr::ExternalImageType::Buffer(),
+                   channelIndex);
+}
+
+void TransactionBuilder::UpdateImageBuffer(ImageKey aKey,
+                                           const ImageDescriptor& aDescriptor,
+                                           wr::Vec<uint8_t>& aBytes) {
+  wr_resource_updates_update_image(mTxn, aKey, &aDescriptor, &aBytes.inner);
+}
+
+void TransactionBuilder::UpdateBlobImage(BlobImageKey aKey,
+                                         const ImageDescriptor& aDescriptor,
+                                         wr::Vec<uint8_t>& aBytes,
+                                         const wr::DeviceIntRect& aVisibleRect,
+                                         const wr::LayoutIntRect& aDirtyRect) {
+  wr_resource_updates_update_blob_image(mTxn, aKey, &aDescriptor, &aBytes.inner,
+                                        aVisibleRect, aDirtyRect);
+}
+
+void TransactionBuilder::UpdateExternalImage(ImageKey aKey,
+                                             const ImageDescriptor& aDescriptor,
+                                             ExternalImageId aExtID,
+                                             wr::ExternalImageType aImageType,
+                                             uint8_t aChannelIndex) {
+  wr_resource_updates_update_external_image(mTxn, aKey, &aDescriptor, aExtID,
+                                            &aImageType, aChannelIndex);
+}
+
+void TransactionBuilder::UpdateExternalImageWithDirtyRect(
+    ImageKey aKey, const ImageDescriptor& aDescriptor, ExternalImageId aExtID,
+    wr::ExternalImageType aImageType, const wr::DeviceIntRect& aDirtyRect,
+    uint8_t aChannelIndex) {
+  wr_resource_updates_update_external_image_with_dirty_rect(
+      mTxn, aKey, &aDescriptor, aExtID, &aImageType, aChannelIndex, aDirtyRect);
+}
+
+void TransactionBuilder::SetBlobImageVisibleArea(
+    BlobImageKey aKey, const wr::DeviceIntRect& aArea) {
+  wr_resource_updates_set_blob_image_visible_area(mTxn, aKey, &aArea);
+}
+
+void TransactionBuilder::DeleteImage(ImageKey aKey) {
+  wr_resource_updates_delete_image(mTxn, aKey);
+}
+
+void TransactionBuilder::DeleteBlobImage(BlobImageKey aKey) {
+  wr_resource_updates_delete_blob_image(mTxn, aKey);
+}
+
+void TransactionBuilder::AddRawFont(wr::FontKey aKey, wr::Vec<uint8_t>& aBytes,
+                                    uint32_t aIndex) {
+  wr_resource_updates_add_raw_font(mTxn, aKey, &aBytes.inner, aIndex);
+}
+
+void TransactionBuilder::AddFontDescriptor(wr::FontKey aKey,
+                                           wr::Vec<uint8_t>& aBytes,
+                                           uint32_t aIndex) {
+  wr_resource_updates_add_font_descriptor(mTxn, aKey, &aBytes.inner, aIndex);
+}
+
+void TransactionBuilder::DeleteFont(wr::FontKey aKey) {
+  wr_resource_updates_delete_font(mTxn, aKey);
+}
+
+void TransactionBuilder::AddFontInstance(
+    wr::FontInstanceKey aKey, wr::FontKey aFontKey, float aGlyphSize,
+    const wr::FontInstanceOptions* aOptions,
+    const wr::FontInstancePlatformOptions* aPlatformOptions,
+    wr::Vec<uint8_t>& aVariations) {
+  wr_resource_updates_add_font_instance(mTxn, aKey, aFontKey, aGlyphSize,
+                                        aOptions, aPlatformOptions,
+                                        &aVariations.inner);
+}
+
+void TransactionBuilder::DeleteFontInstance(wr::FontInstanceKey aKey) {
+  wr_resource_updates_delete_font_instance(mTxn, aKey);
+}
+
+void TransactionBuilder::UpdateQualitySettings(
+    bool aForceSubpixelAAWherePossible) {
+  wr_transaction_set_quality_settings(mTxn, aForceSubpixelAAWherePossible);
+}
+
+class FrameStartTime : public RendererEvent {
+ public:
+  explicit FrameStartTime(const TimeStamp& aTime) : mTime(aTime) {
+    MOZ_COUNT_CTOR(FrameStartTime);
+  }
+
+  MOZ_COUNTED_DTOR_OVERRIDE(FrameStartTime)
+
+  void Run(RenderThread& aRenderThread, WindowId aWindowId) override {
+    auto renderer = aRenderThread.GetRenderer(aWindowId);
+    if (renderer) {
+      renderer->SetFrameStartTime(mTime);
+    }
+  }
+
+ private:
+  TimeStamp mTime;
+};
+
+void WebRenderAPI::SetFrameStartTime(const TimeStamp& aTime) {
+  auto event = MakeUnique<FrameStartTime>(aTime);
+  RunOnRenderThread(std::move(event));
+}
+
+void WebRenderAPI::RunOnRenderThread(UniquePtr<RendererEvent> aEvent) {
+  auto event = reinterpret_cast<uintptr_t>(aEvent.release());
+  wr_api_send_external_event(mDocHandle, event);
+}
+
+DisplayListBuilder::DisplayListBuilder(PipelineId aId,
+                                       WebRenderBackend aBackend)
+    : mCurrentSpaceAndClipChain(wr::RootScrollNodeWithChain()),
+      mActiveFixedPosTracker(nullptr),
+      mPipelineId(aId),
+      mBackend(aBackend),
+      mDisplayItemCache(nullptr) {
+  MOZ_COUNT_CTOR(DisplayListBuilder);
+  mWrState = wr_state_new(aId);
+
+  if (mDisplayItemCache && mDisplayItemCache->IsEnabled()) {
+    mDisplayItemCache->SetPipelineId(aId);
+  }
+}
+
+DisplayListBuilder::~DisplayListBuilder() {
+  MOZ_COUNT_DTOR(DisplayListBuilder);
+  wr_state_delete(mWrState);
+}
+
+void DisplayListBuilder::Save() { wr_dp_save(mWrState); }
+void DisplayListBuilder::Restore() { wr_dp_restore(mWrState); }
+void DisplayListBuilder::ClearSave() { wr_dp_clear_save(mWrState); }
+
+usize DisplayListBuilder::Dump(usize aIndent, const Maybe<usize>& aStart,
+                               const Maybe<usize>& aEnd) {
+  return wr_dump_display_list(mWrState, aIndent, aStart.ptrOr(nullptr),
+                              aEnd.ptrOr(nullptr));
+}
+
+void DisplayListBuilder::DumpSerializedDisplayList() {
+  wr_dump_serialized_display_list(mWrState);
+}
+
+void DisplayListBuilder::Begin(layers::DisplayItemCache* aCache) {
+  wr_api_begin_builder(mWrState);
+
+  mScrollIds.clear();
+  mCurrentSpaceAndClipChain = wr::RootScrollNodeWithChain();
+  mClipChainLeaf = Nothing();
+  mSuspendedSpaceAndClipChain = Nothing();
+  mSuspendedClipChainLeaf = Nothing();
+  mCachedTextDT = nullptr;
+  mCachedContext = nullptr;
+  mActiveFixedPosTracker = nullptr;
+  mDisplayItemCache = aCache;
+  mCurrentCacheSlot = Nothing();
+  mRemotePipelineIds.Clear();
+}
+
+void DisplayListBuilder::End(BuiltDisplayList& aOutDisplayList) {
+  wr_api_end_builder(
+      mWrState, &aOutDisplayList.dl_desc, &aOutDisplayList.dl_items.inner,
+      &aOutDisplayList.dl_cache.inner, &aOutDisplayList.dl_spatial_tree.inner);
+
+  mDisplayItemCache = nullptr;
+}
+
+void DisplayListBuilder::End(layers::DisplayListData& aOutTransaction) {
+  if (mDisplayItemCache && mDisplayItemCache->IsEnabled()) {
+    wr_dp_set_cache_size(mWrState, mDisplayItemCache->CurrentSize());
+  }
+
+  wr::VecU8 dlItems, dlCache, dlSpatialTree;
+  wr_api_end_builder(mWrState, &aOutTransaction.mDLDesc, &dlItems.inner,
+                     &dlCache.inner, &dlSpatialTree.inner);
+  aOutTransaction.mDLItems.emplace(dlItems.inner.data, dlItems.inner.length,
+                                   dlItems.inner.capacity);
+  aOutTransaction.mDLCache.emplace(dlCache.inner.data, dlCache.inner.length,
+                                   dlCache.inner.capacity);
+  aOutTransaction.mDLSpatialTree.emplace(dlSpatialTree.inner.data,
+                                         dlSpatialTree.inner.length,
+                                         dlSpatialTree.inner.capacity);
+  aOutTransaction.mRemotePipelineIds = mRemotePipelineIds.Clone();
+  dlItems.inner.capacity = 0;
+  dlItems.inner.data = nullptr;
+  dlCache.inner.capacity = 0;
+  dlCache.inner.data = nullptr;
+  dlSpatialTree.inner.capacity = 0;
+  dlSpatialTree.inner.data = nullptr;
+}
+
+Maybe<wr::WrSpatialId> DisplayListBuilder::PushStackingContext(
+    const wr::StackingContextParams& aParams, const wr::LayoutRect& aBounds,
+    const wr::RasterSpace& aRasterSpace) {
+  MOZ_ASSERT(mClipChainLeaf.isNothing(),
+             "Non-empty leaf from clip chain given, but not used with SC!");
+
+  WRDL_LOG(
+      "PushStackingContext b=%s t=%s id=0x%" PRIx64 "\n", mWrState,
+      ToString(aBounds).c_str(),
+      aParams.mTransformPtr ? ToString(*aParams.mTransformPtr).c_str() : "none",
+      aParams.animation ? aParams.animation->id : 0);
+
+  auto spatialId = wr_dp_push_stacking_context(
+      mWrState, aBounds, mCurrentSpaceAndClipChain.space, &aParams,
+      aParams.mTransformPtr, aParams.mFilters.Elements(),
+      aParams.mFilters.Length(), aParams.mFilterDatas.Elements(),
+      aParams.mFilterDatas.Length(), aRasterSpace);
+
+  return spatialId.id != 0 ? Some(spatialId) : Nothing();
+}
+
+void DisplayListBuilder::PopStackingContext(bool aIsReferenceFrame) {
+  WRDL_LOG("PopStackingContext\n", mWrState);
+  wr_dp_pop_stacking_context(mWrState, aIsReferenceFrame);
+}
+
+wr::WrClipChainId DisplayListBuilder::DefineClipChain(
+    const nsTArray<wr::WrClipId>& aClips, bool aParentWithCurrentChain) {
+  CancelGroup();
+
+  const uint64_t* parent = nullptr;
+  if (aParentWithCurrentChain &&
+      mCurrentSpaceAndClipChain.clip_chain != wr::ROOT_CLIP_CHAIN) {
+    parent = &mCurrentSpaceAndClipChain.clip_chain;
+  }
+  uint64_t clipchainId = wr_dp_define_clipchain(
+      mWrState, parent, aClips.Elements(), aClips.Length());
+  WRDL_LOG("DefineClipChain id=%" PRIu64 " clips=%zu\n", mWrState, clipchainId,
+           aClips.Length());
+  return wr::WrClipChainId{clipchainId};
+}
+
+wr::WrClipId DisplayListBuilder::DefineImageMaskClip(
+    const wr::ImageMask& aMask, const nsTArray<wr::LayoutPoint>& aPoints,
+    wr::FillRule aFillRule) {
+  CancelGroup();
+
+  WrClipId clipId = wr_dp_define_image_mask_clip_with_parent_clip_chain(
+      mWrState, mCurrentSpaceAndClipChain.space, aMask, aPoints.Elements(),
+      aPoints.Length(), aFillRule);
+
+  return clipId;
+}
+
+wr::WrClipId DisplayListBuilder::DefineRoundedRectClip(
+    Maybe<wr::WrSpatialId> aSpace, const wr::ComplexClipRegion& aComplex) {
+  CancelGroup();
+
+  WrClipId clipId;
+  if (aSpace) {
+    clipId = wr_dp_define_rounded_rect_clip(mWrState, *aSpace, aComplex);
+  } else {
+    clipId = wr_dp_define_rounded_rect_clip(
+        mWrState, mCurrentSpaceAndClipChain.space, aComplex);
+  }
+
+  return clipId;
+}
+
+wr::WrClipId DisplayListBuilder::DefineRectClip(Maybe<wr::WrSpatialId> aSpace,
+                                                wr::LayoutRect aClipRect) {
+  CancelGroup();
+
+  WrClipId clipId;
+  if (aSpace) {
+    clipId = wr_dp_define_rect_clip(mWrState, *aSpace, aClipRect);
+  } else {
+    clipId = wr_dp_define_rect_clip(mWrState, mCurrentSpaceAndClipChain.space,
+                                    aClipRect);
+  }
+
+  return clipId;
+}
+
+wr::WrSpatialId DisplayListBuilder::DefineStickyFrame(
+    const wr::LayoutRect& aContentRect, const float* aTopMargin,
+    const float* aRightMargin, const float* aBottomMargin,
+    const float* aLeftMargin, const StickyOffsetBounds& aVerticalBounds,
+    const StickyOffsetBounds& aHorizontalBounds,
+    const wr::LayoutVector2D& aAppliedOffset, wr::SpatialTreeItemKey aKey) {
+  auto spatialId = wr_dp_define_sticky_frame(
+      mWrState, mCurrentSpaceAndClipChain.space, aContentRect, aTopMargin,
+      aRightMargin, aBottomMargin, aLeftMargin, aVerticalBounds,
+      aHorizontalBounds, aAppliedOffset, aKey);
+
+  WRDL_LOG("DefineSticky id=%zu c=%s t=%s r=%s b=%s l=%s v=%s h=%s a=%s\n",
+           mWrState, spatialId.id, ToString(aContentRect).c_str(),
+           aTopMargin ? ToString(*aTopMargin).c_str() : "none",
+           aRightMargin ? ToString(*aRightMargin).c_str() : "none",
+           aBottomMargin ? ToString(*aBottomMargin).c_str() : "none",
+           aLeftMargin ? ToString(*aLeftMargin).c_str() : "none",
+           ToString(aVerticalBounds).c_str(),
+           ToString(aHorizontalBounds).c_str(),
+           ToString(aAppliedOffset).c_str());
+
+  return spatialId;
+}
+
+Maybe<wr::WrSpatialId> DisplayListBuilder::GetScrollIdForDefinedScrollLayer(
+    layers::ScrollableLayerGuid::ViewID aViewId) const {
+  if (aViewId == layers::ScrollableLayerGuid::NULL_SCROLL_ID) {
+    return Some(wr::RootScrollNode());
+  }
+
+  auto it = mScrollIds.find(aViewId);
+  if (it == mScrollIds.end()) {
+    return Nothing();
+  }
+
+  return Some(it->second);
+}
+
+wr::WrSpatialId DisplayListBuilder::DefineScrollLayer(
+    const layers::ScrollableLayerGuid::ViewID& aViewId,
+    const Maybe<wr::WrSpatialId>& aParent, const wr::LayoutRect& aContentRect,
+    const wr::LayoutRect& aClipRect, const wr::LayoutVector2D& aScrollOffset,
+    wr::APZScrollGeneration aScrollOffsetGeneration,
+    wr::HasScrollLinkedEffect aHasScrollLinkedEffect,
+    wr::SpatialTreeItemKey aKey) {
+  auto it = mScrollIds.find(aViewId);
+  if (it != mScrollIds.end()) {
+    return it->second;
+  }
+
+  // We haven't defined aViewId before, so let's define it now.
+  wr::WrSpatialId defaultParent = mCurrentSpaceAndClipChain.space;
+
+  auto space = wr_dp_define_scroll_layer(
+      mWrState, aViewId, aParent ? aParent.ptr() : &defaultParent, aContentRect,
+      aClipRect, aScrollOffset, aScrollOffsetGeneration, aHasScrollLinkedEffect,
+      aKey);
+
+  WRDL_LOG("DefineScrollLayer id=%" PRIu64
+           "/%zu p=%s co=%s cl=%s generation=%s hasScrollLinkedEffect=%s\n",
+           mWrState, aViewId, space.id,
+           aParent ? ToString(aParent->id).c_str() : "(nil)",
+           ToString(aContentRect).c_str(), ToString(aClipRect).c_str(),
+           ToString(aScrollOffsetGeneration).c_str(),
+           ToString(aHasScrollLinkedEffect).c_str());
+
+  mScrollIds[aViewId] = space;
+  return space;
+}
+
+void DisplayListBuilder::PushRect(const wr::LayoutRect& aBounds,
+                                  const wr::LayoutRect& aClip,
+                                  bool aIsBackfaceVisible,
+                                  bool aForceAntiAliasing, bool aIsCheckerboard,
+                                  const wr::ColorF& aColor) {
+  wr::LayoutRect clip = MergeClipLeaf(aClip);
+  WRDL_LOG("PushRect b=%s cl=%s c=%s\n", mWrState, ToString(aBounds).c_str(),
+           ToString(clip).c_str(), ToString(aColor).c_str());
+  wr_dp_push_rect(mWrState, aBounds, clip, aIsBackfaceVisible,
+                  aForceAntiAliasing, aIsCheckerboard,
+                  &mCurrentSpaceAndClipChain, aColor);
+}
+
+void DisplayListBuilder::PushRoundedRect(const wr::LayoutRect& aBounds,
+                                         const wr::LayoutRect& aClip,
+                                         bool aIsBackfaceVisible,
+                                         const wr::ColorF& aColor) {
+  wr::LayoutRect clip = MergeClipLeaf(aClip);
+  WRDL_LOG("PushRoundedRect b=%s cl=%s c=%s\n", mWrState,
+           ToString(aBounds).c_str(), ToString(clip).c_str(),
+           ToString(aColor).c_str());
+
+  // Draw the rounded rectangle as a border with rounded corners. We could also
+  // draw this as a rectangle clipped to a rounded rectangle, but:
+  // - clips are not cached; borders are
+  // - a simple border like this will be drawn as an image
+  // - Processing lots of clips is not WebRender's strong point.
+  //
+  // Made the borders thicker than one half the width/height, to avoid
+  // little white dots at the center at some magnifications.
+  wr::BorderSide side = {aColor, wr::BorderStyle::Solid};
+  float h = aBounds.width() * 0.6f;
+  float v = aBounds.height() * 0.6f;
+  wr::LayoutSideOffsets widths = {v, h, v, h};
+  wr::BorderRadius radii = {{h, v}, {h, v}, {h, v}, {h, v}};
+
+  // Anti-aliased borders are required for rounded borders.
+  wr_dp_push_border(mWrState, aBounds, clip, aIsBackfaceVisible,
+                    &mCurrentSpaceAndClipChain, wr::AntialiasBorder::Yes,
+                    widths, side, side, side, side, radii);
+}
+
+void DisplayListBuilder::PushHitTest(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible,
+    const layers::ScrollableLayerGuid::ViewID& aScrollId,
+    const gfx::CompositorHitTestInfo& aHitInfo, SideBits aSideBits) {
+  wr::LayoutRect clip = MergeClipLeaf(aClip);
+  WRDL_LOG("PushHitTest b=%s cl=%s\n", mWrState, ToString(aBounds).c_str(),
+           ToString(clip).c_str());
+
+  static_assert(gfx::DoesCompositorHitTestInfoFitIntoBits<12>(),
+                "CompositorHitTestFlags MAX value has to be less than number "
+                "of bits in uint16_t minus 4 for SideBitsPacked");
+
+  uint16_t hitInfoBits = static_cast<uint16_t>(aHitInfo.serialize()) |
+                         (static_cast<uint16_t>(aSideBits) << 12);
+
+  wr_dp_push_hit_test(mWrState, aBounds, clip, aIsBackfaceVisible,
+                      &mCurrentSpaceAndClipChain, aScrollId, hitInfoBits);
+}
+
+void DisplayListBuilder::PushRectWithAnimation(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, const wr::ColorF& aColor,
+    const WrAnimationProperty* aAnimation) {
+  wr::LayoutRect clip = MergeClipLeaf(aClip);
+  WRDL_LOG("PushRectWithAnimation b=%s cl=%s c=%s\n", mWrState,
+           ToString(aBounds).c_str(), ToString(clip).c_str(),
+           ToString(aColor).c_str());
+
+  wr_dp_push_rect_with_animation(mWrState, aBounds, clip, aIsBackfaceVisible,
+                                 &mCurrentSpaceAndClipChain, aColor,
+                                 aAnimation);
+}
+
+void DisplayListBuilder::PushClearRect(const wr::LayoutRect& aBounds) {
+  wr::LayoutRect clip = MergeClipLeaf(aBounds);
+  WRDL_LOG("PushClearRect b=%s c=%s\n", mWrState, ToString(aBounds).c_str(),
+           ToString(clip).c_str());
+  wr_dp_push_clear_rect(mWrState, aBounds, clip, &mCurrentSpaceAndClipChain);
+}
+
+void DisplayListBuilder::PushBackdropFilter(
+    const wr::LayoutRect& aBounds, const wr::ComplexClipRegion& aRegion,
+    const nsTArray<wr::FilterOp>& aFilters,
+    const nsTArray<wr::WrFilterData>& aFilterDatas, bool aIsBackfaceVisible) {
+  wr::LayoutRect clip = MergeClipLeaf(aBounds);
+  WRDL_LOG("PushBackdropFilter b=%s c=%s\n", mWrState,
+           ToString(aBounds).c_str(), ToString(clip).c_str());
+
+  auto clipId = DefineRoundedRectClip(Nothing(), aRegion);
+  auto clipChainId = DefineClipChain({clipId}, true);
+  auto spaceAndClip =
+      WrSpaceAndClipChain{mCurrentSpaceAndClipChain.space, clipChainId.id};
+
+  wr_dp_push_backdrop_filter(mWrState, aBounds, clip, aIsBackfaceVisible,
+                             &spaceAndClip, aFilters.Elements(),
+                             aFilters.Length(), aFilterDatas.Elements(),
+                             aFilterDatas.Length());
+}
+
+void DisplayListBuilder::PushLinearGradient(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, const wr::LayoutPoint& aStartPoint,
+    const wr::LayoutPoint& aEndPoint, const nsTArray<wr::GradientStop>& aStops,
+    wr::ExtendMode aExtendMode, const wr::LayoutSize aTileSize,
+    const wr::LayoutSize aTileSpacing) {
+  wr_dp_push_linear_gradient(
+      mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+      &mCurrentSpaceAndClipChain, aStartPoint, aEndPoint, aStops.Elements(),
+      aStops.Length(), aExtendMode, aTileSize, aTileSpacing);
+}
+
+void DisplayListBuilder::PushRadialGradient(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, const wr::LayoutPoint& aCenter,
+    const wr::LayoutSize& aRadius, const nsTArray<wr::GradientStop>& aStops,
+    wr::ExtendMode aExtendMode, const wr::LayoutSize aTileSize,
+    const wr::LayoutSize aTileSpacing) {
+  wr_dp_push_radial_gradient(
+      mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+      &mCurrentSpaceAndClipChain, aCenter, aRadius, aStops.Elements(),
+      aStops.Length(), aExtendMode, aTileSize, aTileSpacing);
+}
+
+void DisplayListBuilder::PushConicGradient(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, const wr::LayoutPoint& aCenter, const float aAngle,
+    const nsTArray<wr::GradientStop>& aStops, wr::ExtendMode aExtendMode,
+    const wr::LayoutSize aTileSize, const wr::LayoutSize aTileSpacing) {
+  wr_dp_push_conic_gradient(mWrState, aBounds, MergeClipLeaf(aClip),
+                            aIsBackfaceVisible, &mCurrentSpaceAndClipChain,
+                            aCenter, aAngle, aStops.Elements(), aStops.Length(),
+                            aExtendMode, aTileSize, aTileSpacing);
+}
+
+void DisplayListBuilder::PushImage(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, bool aForceAntiAliasing,
+    wr::ImageRendering aFilter, wr::ImageKey aImage, bool aPremultipliedAlpha,
+    const wr::ColorF& aColor, bool aPreferCompositorSurface,
+    bool aSupportsExternalCompositing) {
+  wr::LayoutRect clip = MergeClipLeaf(aClip);
+  WRDL_LOG("PushImage b=%s cl=%s\n", mWrState, ToString(aBounds).c_str(),
+           ToString(clip).c_str());
+  wr_dp_push_image(mWrState, aBounds, clip, aIsBackfaceVisible,
+                   aForceAntiAliasing, &mCurrentSpaceAndClipChain, aFilter,
+                   aImage, aPremultipliedAlpha, aColor,
+                   aPreferCompositorSurface, aSupportsExternalCompositing);
+}
+
+void DisplayListBuilder::PushRepeatingImage(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, const wr::LayoutSize& aStretchSize,
+    const wr::LayoutSize& aTileSpacing, wr::ImageRendering aFilter,
+    wr::ImageKey aImage, bool aPremultipliedAlpha, const wr::ColorF& aColor) {
+  wr::LayoutRect clip = MergeClipLeaf(aClip);
+  WRDL_LOG("PushImage b=%s cl=%s s=%s t=%s\n", mWrState,
+           ToString(aBounds).c_str(), ToString(clip).c_str(),
+           ToString(aStretchSize).c_str(), ToString(aTileSpacing).c_str());
+  wr_dp_push_repeating_image(
+      mWrState, aBounds, clip, aIsBackfaceVisible, &mCurrentSpaceAndClipChain,
+      aStretchSize, aTileSpacing, aFilter, aImage, aPremultipliedAlpha, aColor);
+}
+
+void DisplayListBuilder::PushYCbCrPlanarImage(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, wr::ImageKey aImageChannel0,
+    wr::ImageKey aImageChannel1, wr::ImageKey aImageChannel2,
+    wr::WrColorDepth aColorDepth, wr::WrYuvColorSpace aColorSpace,
+    wr::WrColorRange aColorRange, wr::ImageRendering aRendering,
+    bool aPreferCompositorSurface, bool aSupportsExternalCompositing) {
+  wr_dp_push_yuv_planar_image(
+      mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+      &mCurrentSpaceAndClipChain, aImageChannel0, aImageChannel1,
+      aImageChannel2, aColorDepth, aColorSpace, aColorRange, aRendering,
+      aPreferCompositorSurface, aSupportsExternalCompositing);
+}
+
+void DisplayListBuilder::PushNV12Image(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, wr::ImageKey aImageChannel0,
+    wr::ImageKey aImageChannel1, wr::WrColorDepth aColorDepth,
+    wr::WrYuvColorSpace aColorSpace, wr::WrColorRange aColorRange,
+    wr::ImageRendering aRendering, bool aPreferCompositorSurface,
+    bool aSupportsExternalCompositing) {
+  wr_dp_push_yuv_NV12_image(
+      mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+      &mCurrentSpaceAndClipChain, aImageChannel0, aImageChannel1, aColorDepth,
+      aColorSpace, aColorRange, aRendering, aPreferCompositorSurface,
+      aSupportsExternalCompositing);
+}
+
+void DisplayListBuilder::PushP010Image(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, wr::ImageKey aImageChannel0,
+    wr::ImageKey aImageChannel1, wr::WrColorDepth aColorDepth,
+    wr::WrYuvColorSpace aColorSpace, wr::WrColorRange aColorRange,
+    wr::ImageRendering aRendering, bool aPreferCompositorSurface,
+    bool aSupportsExternalCompositing) {
+  wr_dp_push_yuv_P010_image(
+      mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+      &mCurrentSpaceAndClipChain, aImageChannel0, aImageChannel1, aColorDepth,
+      aColorSpace, aColorRange, aRendering, aPreferCompositorSurface,
+      aSupportsExternalCompositing);
+}
+
+void DisplayListBuilder::PushYCbCrInterleavedImage(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, wr::ImageKey aImageChannel0,
+    wr::WrColorDepth aColorDepth, wr::WrYuvColorSpace aColorSpace,
+    wr::WrColorRange aColorRange, wr::ImageRendering aRendering,
+    bool aPreferCompositorSurface, bool aSupportsExternalCompositing) {
+  wr_dp_push_yuv_interleaved_image(
+      mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+      &mCurrentSpaceAndClipChain, aImageChannel0, aColorDepth, aColorSpace,
+      aColorRange, aRendering, aPreferCompositorSurface,
+      aSupportsExternalCompositing);
+}
+
+void DisplayListBuilder::PushIFrame(const LayoutDeviceRect& aDevPxBounds,
+                                    bool aIsBackfaceVisible,
+                                    PipelineId aPipeline,
+                                    bool aIgnoreMissingPipeline) {
+  mRemotePipelineIds.AppendElement(aPipeline);
+  // If the incoming bounds size has decimals (As it could when zoom is
+  // involved), and is pushed straight through here, the compositor would end up
+  // calculating the destination rect to paint the rendered iframe into
+  // with those decimal values, rounding the result, instead of snapping. This
+  // can cause the rendered iframe rect and its destination rect to be
+  // mismatched, resulting in interpolation artifacts.
+  auto snapped = aDevPxBounds;
+  auto tl = snapped.TopLeft().Round();
+  auto br = snapped.BottomRight().Round();
+
+  snapped.SizeTo(LayoutDeviceSize(br.x - tl.x, br.y - tl.y));
+
+  const auto bounds = wr::ToLayoutRect(snapped);
+  wr_dp_push_iframe(mWrState, bounds, MergeClipLeaf(bounds), aIsBackfaceVisible,
+                    &mCurrentSpaceAndClipChain, aPipeline,
+                    aIgnoreMissingPipeline);
+}
+
+void DisplayListBuilder::PushBorder(const wr::LayoutRect& aBounds,
+                                    const wr::LayoutRect& aClip,
+                                    bool aIsBackfaceVisible,
+                                    const wr::LayoutSideOffsets& aWidths,
+                                    const Range<const wr::BorderSide>& aSides,
+                                    const wr::BorderRadius& aRadius,
+                                    wr::AntialiasBorder aAntialias) {
+  MOZ_ASSERT(aSides.length() == 4);
+  if (aSides.length() != 4) {
+    return;
+  }
+  wr_dp_push_border(mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+                    &mCurrentSpaceAndClipChain, aAntialias, aWidths, aSides[0],
+                    aSides[1], aSides[2], aSides[3], aRadius);
+}
+
+void DisplayListBuilder::PushBorderImage(const wr::LayoutRect& aBounds,
+                                         const wr::LayoutRect& aClip,
+                                         bool aIsBackfaceVisible,
+                                         const wr::WrBorderImage& aParams) {
+  wr_dp_push_border_image(mWrState, aBounds, MergeClipLeaf(aClip),
+                          aIsBackfaceVisible, &mCurrentSpaceAndClipChain,
+                          &aParams);
+}
+
+void DisplayListBuilder::PushBorderGradient(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, const wr::LayoutSideOffsets& aWidths,
+    const int32_t aWidth, const int32_t aHeight, bool aFill,
+    const wr::DeviceIntSideOffsets& aSlice, const wr::LayoutPoint& aStartPoint,
+    const wr::LayoutPoint& aEndPoint, const nsTArray<wr::GradientStop>& aStops,
+    wr::ExtendMode aExtendMode) {
+  wr_dp_push_border_gradient(
+      mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+      &mCurrentSpaceAndClipChain, aWidths, aWidth, aHeight, aFill, aSlice,
+      aStartPoint, aEndPoint, aStops.Elements(), aStops.Length(), aExtendMode);
+}
+
+void DisplayListBuilder::PushBorderRadialGradient(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, const wr::LayoutSideOffsets& aWidths, bool aFill,
+    const wr::LayoutPoint& aCenter, const wr::LayoutSize& aRadius,
+    const nsTArray<wr::GradientStop>& aStops, wr::ExtendMode aExtendMode) {
+  wr_dp_push_border_radial_gradient(
+      mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+      &mCurrentSpaceAndClipChain, aWidths, aFill, aCenter, aRadius,
+      aStops.Elements(), aStops.Length(), aExtendMode);
+}
+
+void DisplayListBuilder::PushBorderConicGradient(
+    const wr::LayoutRect& aBounds, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, const wr::LayoutSideOffsets& aWidths, bool aFill,
+    const wr::LayoutPoint& aCenter, const float aAngle,
+    const nsTArray<wr::GradientStop>& aStops, wr::ExtendMode aExtendMode) {
+  wr_dp_push_border_conic_gradient(
+      mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+      &mCurrentSpaceAndClipChain, aWidths, aFill, aCenter, aAngle,
+      aStops.Elements(), aStops.Length(), aExtendMode);
+}
+
+void DisplayListBuilder::PushText(const wr::LayoutRect& aBounds,
+                                  const wr::LayoutRect& aClip,
+                                  bool aIsBackfaceVisible,
+                                  const wr::ColorF& aColor,
+                                  wr::FontInstanceKey aFontKey,
+                                  Range<const wr::GlyphInstance> aGlyphBuffer,
+                                  const wr::GlyphOptions* aGlyphOptions) {
+  wr_dp_push_text(mWrState, aBounds, MergeClipLeaf(aClip), aIsBackfaceVisible,
+                  &mCurrentSpaceAndClipChain, aColor, aFontKey,
+                  &aGlyphBuffer[0], aGlyphBuffer.length(), aGlyphOptions);
+}
+
+void DisplayListBuilder::PushLine(const wr::LayoutRect& aClip,
+                                  bool aIsBackfaceVisible,
+                                  const wr::Line& aLine) {
+  wr::LayoutRect clip = MergeClipLeaf(aClip);
+  wr_dp_push_line(mWrState, &clip, aIsBackfaceVisible,
+                  &mCurrentSpaceAndClipChain, &aLine.bounds,
+                  aLine.wavyLineThickness, aLine.orientation, &aLine.color,
+                  aLine.style);
+}
+
+void DisplayListBuilder::PushShadow(const wr::LayoutRect& aRect,
+                                    const wr::LayoutRect& aClip,
+                                    bool aIsBackfaceVisible,
+                                    const wr::Shadow& aShadow,
+                                    bool aShouldInflate) {
+  // Local clip_rects are translated inside of shadows, as they are assumed to
+  // be part of the element drawing itself, and not a parent frame clipping it.
+  // As such, it is not sound to apply the MergeClipLeaf optimization inside of
+  // shadows. So we disable the optimization when we encounter a shadow.
+  // Shadows don't span frames, so we don't have to worry about MergeClipLeaf
+  // being re-enabled mid-shadow. The optimization is restored in PopAllShadows.
+  SuspendClipLeafMerging();
+  wr_dp_push_shadow(mWrState, aRect, aClip, aIsBackfaceVisible,
+                    &mCurrentSpaceAndClipChain, aShadow, aShouldInflate);
+}
+
+void DisplayListBuilder::PopAllShadows() {
+  wr_dp_pop_all_shadows(mWrState);
+  ResumeClipLeafMerging();
+}
+
+void DisplayListBuilder::SuspendClipLeafMerging() {
+  if (mClipChainLeaf) {
+    // No one should reinitialize mClipChainLeaf while we're suspended
+    MOZ_ASSERT(!mSuspendedClipChainLeaf);
+
+    mSuspendedClipChainLeaf = mClipChainLeaf;
+    mSuspendedSpaceAndClipChain = Some(mCurrentSpaceAndClipChain);
+
+    auto clipId = DefineRectClip(Nothing(), *mClipChainLeaf);
+    auto clipChainId = DefineClipChain({clipId}, true);
+
+    mCurrentSpaceAndClipChain.clip_chain = clipChainId.id;
+    mClipChainLeaf = Nothing();
+  }
+}
+
+void DisplayListBuilder::ResumeClipLeafMerging() {
+  if (mSuspendedClipChainLeaf) {
+    mCurrentSpaceAndClipChain = *mSuspendedSpaceAndClipChain;
+    mClipChainLeaf = mSuspendedClipChainLeaf;
+
+    mSuspendedClipChainLeaf = Nothing();
+    mSuspendedSpaceAndClipChain = Nothing();
+  }
+}
+
+void DisplayListBuilder::PushBoxShadow(
+    const wr::LayoutRect& aRect, const wr::LayoutRect& aClip,
+    bool aIsBackfaceVisible, const wr::LayoutRect& aBoxBounds,
+    const wr::LayoutVector2D& aOffset, const wr::ColorF& aColor,
+    const float& aBlurRadius, const float& aSpreadRadius,
+    const wr::BorderRadius& aBorderRadius,
+    const wr::BoxShadowClipMode& aClipMode) {
+  wr_dp_push_box_shadow(mWrState, aRect, MergeClipLeaf(aClip),
+                        aIsBackfaceVisible, &mCurrentSpaceAndClipChain,
+                        aBoxBounds, aOffset, aColor, aBlurRadius, aSpreadRadius,
+                        aBorderRadius, aClipMode);
+}
+
+void DisplayListBuilder::StartGroup(nsPaintedDisplayItem* aItem) {
+  if (!mDisplayItemCache || mDisplayItemCache->IsFull()) {
+    return;
+  }
+
+  MOZ_ASSERT(!mCurrentCacheSlot);
+  mCurrentCacheSlot = mDisplayItemCache->AssignSlot(aItem);
+
+  if (mCurrentCacheSlot) {
+    wr_dp_start_item_group(mWrState);
+  }
+}
+
+void DisplayListBuilder::CancelGroup(const bool aDiscard) {
+  if (!mDisplayItemCache || !mCurrentCacheSlot) {
+    return;
+  }
+
+  wr_dp_cancel_item_group(mWrState, aDiscard);
+  mCurrentCacheSlot = Nothing();
+}
+
+void DisplayListBuilder::FinishGroup() {
+  if (!mDisplayItemCache || !mCurrentCacheSlot) {
+    return;
+  }
+
+  MOZ_ASSERT(mCurrentCacheSlot);
+
+  if (wr_dp_finish_item_group(mWrState, mCurrentCacheSlot.ref())) {
+    mDisplayItemCache->MarkSlotOccupied(mCurrentCacheSlot.ref(),
+                                        CurrentSpaceAndClipChain());
+    mDisplayItemCache->Stats().AddCached();
+  }
+
+  mCurrentCacheSlot = Nothing();
+}
+
+bool DisplayListBuilder::ReuseItem(nsPaintedDisplayItem* aItem) {
+  if (!mDisplayItemCache) {
+    return false;
+  }
+
+  mDisplayItemCache->Stats().AddTotal();
+
+  if (mDisplayItemCache->IsEmpty()) {
+    return false;
+  }
+
+  Maybe<uint16_t> slot =
+      mDisplayItemCache->CanReuseItem(aItem, CurrentSpaceAndClipChain());
+
+  if (slot) {
+    mDisplayItemCache->Stats().AddReused();
+    wr_dp_push_reuse_items(mWrState, slot.ref());
+    return true;
+  }
+
+  return false;
+}
+
+Maybe<layers::ScrollableLayerGuid::ViewID>
+DisplayListBuilder::GetContainingFixedPosScrollTarget(
+    const ActiveScrolledRoot* aAsr) {
+  return mActiveFixedPosTracker
+             ? mActiveFixedPosTracker->GetScrollTargetForASR(aAsr)
+             : Nothing();
+}
+
+Maybe<SideBits> DisplayListBuilder::GetContainingFixedPosSideBits(
+    const ActiveScrolledRoot* aAsr) {
+  return mActiveFixedPosTracker
+             ? mActiveFixedPosTracker->GetSideBitsForASR(aAsr)
+             : Nothing();
+}
+
+DisplayListBuilder::FixedPosScrollTargetTracker::FixedPosScrollTargetTracker(
+    DisplayListBuilder& aBuilder, const ActiveScrolledRoot* aAsr,
+    layers::ScrollableLayerGuid::ViewID aScrollId, SideBits aSideBits)
+    : mParentTracker(aBuilder.mActiveFixedPosTracker),
+      mBuilder(aBuilder),
+      mAsr(aAsr),
+      mScrollId(aScrollId),
+      mSideBits(aSideBits) {
+  aBuilder.mActiveFixedPosTracker = this;
+}
+
+DisplayListBuilder::FixedPosScrollTargetTracker::
+    ~FixedPosScrollTargetTracker() {
+  mBuilder.mActiveFixedPosTracker = mParentTracker;
+}
+
+Maybe<layers::ScrollableLayerGuid::ViewID>
+DisplayListBuilder::FixedPosScrollTargetTracker::GetScrollTargetForASR(
+    const ActiveScrolledRoot* aAsr) {
+  return aAsr == mAsr ? Some(mScrollId) : Nothing();
+}
+
+Maybe<SideBits>
+DisplayListBuilder::FixedPosScrollTargetTracker::GetSideBitsForASR(
+    const ActiveScrolledRoot* aAsr) {
+  return aAsr == mAsr ? Some(mSideBits) : Nothing();
+}
+
+gfxContext* DisplayListBuilder::GetTextContext(
+    wr::IpcResourceUpdateQueue& aResources,
+    const layers::StackingContextHelper& aSc,
+    layers::RenderRootStateManager* aManager, nsDisplayItem* aItem,
+    nsRect& aBounds, const gfx::Point& aDeviceOffset) {
+  if (!mCachedTextDT) {
+    mCachedTextDT = new layout::TextDrawTarget(*this, aResources, aSc, aManager,
+                                               aItem, aBounds);
+    if (mCachedTextDT->IsValid()) {
+      mCachedContext = MakeUnique<gfxContext>(mCachedTextDT, aDeviceOffset);
+    }
+  } else {
+    mCachedTextDT->Reinitialize(aResources, aSc, aManager, aItem, aBounds);
+    mCachedContext->SetDeviceOffset(aDeviceOffset);
+    mCachedContext->SetMatrix(gfx::Matrix());
+  }
+
+  return mCachedContext.get();
+}
+
+void DisplayListBuilder::PushInheritedClipChain(
+    nsDisplayListBuilder* aBuilder, const DisplayItemClipChain* aClipChain) {
+  if (!aClipChain || mInheritedClipChain == aClipChain) {
+    return;
+  }
+  if (!mInheritedClipChain) {
+    mInheritedClipChain = aClipChain;
+    return;
+  }
+
+  mInheritedClipChain =
+      aBuilder->CreateClipChainIntersection(mInheritedClipChain, aClipChain);
+}
+
+}  // namespace wr
+}  // namespace mozilla
+
+extern "C" {
+
+void wr_transaction_notification_notified(uintptr_t aHandler,
+                                          mozilla::wr::Checkpoint aWhen) {
+  auto handler = reinterpret_cast<mozilla::wr::NotificationHandler*>(aHandler);
+  handler->Notify(aWhen);
+  // TODO: it would be better to get a callback when the object is destroyed on
+  // the rust side and delete then.
+  delete handler;
+}
+
+void wr_register_thread_local_arena() {
+#ifdef MOZ_MEMORY
+  jemalloc_thread_local_arena(true);
+#endif
+}
+
+}  // extern C