Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 645 insertions, 0 deletions

diff --git a/widget/ContentCache.h b/widget/ContentCache.h
new file mode 100644
index 0000000000..3f8b48425e
--- /dev/null
+++ b/widget/ContentCache.h
@@ -0,0 +1,645 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* 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 mozilla_ContentCache_h
+#define mozilla_ContentCache_h
+
+#include <stdint.h>
+
+#include "mozilla/widget/IMEData.h"
+#include "mozilla/ipc/IPCForwards.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/ToString.h"
+#include "mozilla/WritingModes.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "Units.h"
+
+class nsIWidget;
+
+namespace mozilla {
+
+class ContentCacheInParent;
+
+namespace dom {
+class BrowserParent;
+}  // namespace dom
+
+/**
+ * ContentCache stores various information of the child content.
+ * This class has members which are necessary both in parent process and
+ * content process.
+ */
+
+class ContentCache {
+ public:
+  using RectArray = CopyableTArray<LayoutDeviceIntRect>;
+  using IMENotification = widget::IMENotification;
+
+  ContentCache() = default;
+
+  [[nodiscard]] bool IsValid() const;
+
+ protected:
+  void AssertIfInvalid() const;
+
+  // Whole text in the target
+  Maybe<nsString> mText;
+
+  // Start offset of the composition string.
+  Maybe<uint32_t> mCompositionStart;
+
+  enum { ePrevCharRect = 1, eNextCharRect = 0 };
+
+  struct Selection final {
+    // Following values are offset in "flat text".
+    uint32_t mAnchor;
+    uint32_t mFocus;
+
+    WritingMode mWritingMode;
+
+    bool mHasRange;
+
+    // Character rects at previous and next character of mAnchor and mFocus.
+    // The reason why ContentCache needs to store each previous character of
+    // them is IME may query character rect of the last character of a line
+    // when caret is at the end of the line.
+    // Note that use ePrevCharRect and eNextCharRect for accessing each item.
+    LayoutDeviceIntRect mAnchorCharRects[2];
+    LayoutDeviceIntRect mFocusCharRects[2];
+
+    // Whole rect of selected text. This is empty if the selection is collapsed.
+    LayoutDeviceIntRect mRect;
+
+    Selection() : mAnchor(UINT32_MAX), mFocus(UINT32_MAX), mHasRange(false) {
+      ClearRects();
+    };
+
+    explicit Selection(
+        const IMENotification::SelectionChangeDataBase& aSelectionChangeData)
+        : mAnchor(UINT32_MAX),
+          mFocus(UINT32_MAX),
+          mWritingMode(aSelectionChangeData.GetWritingMode()),
+          mHasRange(aSelectionChangeData.HasRange()) {
+      if (mHasRange) {
+        mAnchor = aSelectionChangeData.AnchorOffset();
+        mFocus = aSelectionChangeData.FocusOffset();
+      }
+    }
+
+    [[nodiscard]] bool IsValidIn(const nsAString& aText) const {
+      return !mHasRange ||
+             (mAnchor <= aText.Length() && mFocus <= aText.Length());
+    }
+
+    explicit Selection(const WidgetQueryContentEvent& aQuerySelectedTextEvent);
+
+    void ClearRects() {
+      for (auto& rect : mAnchorCharRects) {
+        rect.SetEmpty();
+      }
+      for (auto& rect : mFocusCharRects) {
+        rect.SetEmpty();
+      }
+      mRect.SetEmpty();
+    }
+    bool HasRects() const {
+      for (const auto& rect : mAnchorCharRects) {
+        if (!rect.IsEmpty()) {
+          return true;
+        }
+      }
+      for (const auto& rect : mFocusCharRects) {
+        if (!rect.IsEmpty()) {
+          return true;
+        }
+      }
+      return !mRect.IsEmpty();
+    }
+
+    bool IsCollapsed() const { return !mHasRange || mFocus == mAnchor; }
+    bool Reversed() const {
+      MOZ_ASSERT(mHasRange);
+      return mFocus < mAnchor;
+    }
+    uint32_t StartOffset() const {
+      MOZ_ASSERT(mHasRange);
+      return Reversed() ? mFocus : mAnchor;
+    }
+    uint32_t EndOffset() const {
+      MOZ_ASSERT(mHasRange);
+      return Reversed() ? mAnchor : mFocus;
+    }
+    uint32_t Length() const {
+      MOZ_ASSERT(mHasRange);
+      return Reversed() ? mAnchor - mFocus : mFocus - mAnchor;
+    }
+    LayoutDeviceIntRect StartCharRect() const {
+      return Reversed() ? mFocusCharRects[eNextCharRect]
+                        : mAnchorCharRects[eNextCharRect];
+    }
+    LayoutDeviceIntRect EndCharRect() const {
+      return Reversed() ? mAnchorCharRects[eNextCharRect]
+                        : mFocusCharRects[eNextCharRect];
+    }
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const Selection& aSelection) {
+      aStream << "{ ";
+      if (!aSelection.mHasRange) {
+        aStream << "HasRange()=false";
+      } else {
+        aStream << "mAnchor=" << aSelection.mAnchor
+                << ", mFocus=" << aSelection.mFocus << ", mWritingMode="
+                << ToString(aSelection.mWritingMode).c_str();
+      }
+      if (aSelection.HasRects()) {
+        if (aSelection.mAnchor > 0) {
+          aStream << ", mAnchorCharRects[ePrevCharRect]="
+                  << aSelection.mAnchorCharRects[ContentCache::ePrevCharRect];
+        }
+        aStream << ", mAnchorCharRects[eNextCharRect]="
+                << aSelection.mAnchorCharRects[ContentCache::eNextCharRect];
+        if (aSelection.mFocus > 0) {
+          aStream << ", mFocusCharRects[ePrevCharRect]="
+                  << aSelection.mFocusCharRects[ContentCache::ePrevCharRect];
+        }
+        aStream << ", mFocusCharRects[eNextCharRect]="
+                << aSelection.mFocusCharRects[ContentCache::eNextCharRect]
+                << ", mRect=" << aSelection.mRect;
+      }
+      if (aSelection.mHasRange) {
+        aStream << ", Reversed()=" << (aSelection.Reversed() ? "true" : "false")
+                << ", StartOffset()=" << aSelection.StartOffset()
+                << ", EndOffset()=" << aSelection.EndOffset()
+                << ", IsCollapsed()="
+                << (aSelection.IsCollapsed() ? "true" : "false")
+                << ", Length()=" << aSelection.Length();
+      }
+      aStream << " }";
+      return aStream;
+    }
+  };
+  Maybe<Selection> mSelection;
+
+  // Stores first char rect because Yosemite's Japanese IME sometimes tries
+  // to query it.  If there is no text, this is caret rect.
+  LayoutDeviceIntRect mFirstCharRect;
+
+  struct Caret final {
+    uint32_t mOffset = 0u;
+    LayoutDeviceIntRect mRect;
+
+    explicit Caret(uint32_t aOffset, LayoutDeviceIntRect aCaretRect)
+        : mOffset(aOffset), mRect(aCaretRect) {}
+
+    uint32_t Offset() const { return mOffset; }
+    bool HasRect() const { return !mRect.IsEmpty(); }
+
+    [[nodiscard]] bool IsValidIn(const nsAString& aText) const {
+      return mOffset <= aText.Length();
+    }
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const Caret& aCaret) {
+      aStream << "{ mOffset=" << aCaret.mOffset;
+      if (aCaret.HasRect()) {
+        aStream << ", mRect=" << aCaret.mRect;
+      }
+      return aStream << " }";
+    }
+
+   private:
+    // For ParamTraits<Caret>
+    Caret() = default;
+
+    friend struct IPC::ParamTraits<ContentCache::Caret>;
+    ALLOW_DEPRECATED_READPARAM
+  };
+  Maybe<Caret> mCaret;
+
+  struct TextRectArray final {
+    uint32_t mStart = 0u;
+    RectArray mRects;
+
+    explicit TextRectArray(uint32_t aStartOffset) : mStart(aStartOffset) {}
+
+    bool HasRects() const { return Length() > 0; }
+    uint32_t StartOffset() const { return mStart; }
+    uint32_t EndOffset() const {
+      CheckedInt<uint32_t> endOffset =
+          CheckedInt<uint32_t>(mStart) + mRects.Length();
+      return endOffset.isValid() ? endOffset.value() : UINT32_MAX;
+    }
+    uint32_t Length() const { return EndOffset() - mStart; }
+    bool IsOffsetInRange(uint32_t aOffset) const {
+      return StartOffset() <= aOffset && aOffset < EndOffset();
+    }
+    bool IsRangeCompletelyInRange(uint32_t aOffset, uint32_t aLength) const {
+      CheckedInt<uint32_t> endOffset = CheckedInt<uint32_t>(aOffset) + aLength;
+      if (NS_WARN_IF(!endOffset.isValid())) {
+        return false;
+      }
+      return IsOffsetInRange(aOffset) && aOffset + aLength <= EndOffset();
+    }
+    bool IsOverlappingWith(uint32_t aOffset, uint32_t aLength) const {
+      if (!HasRects() || aOffset == UINT32_MAX || !aLength) {
+        return false;
+      }
+      CheckedInt<uint32_t> endOffset = CheckedInt<uint32_t>(aOffset) + aLength;
+      if (NS_WARN_IF(!endOffset.isValid())) {
+        return false;
+      }
+      return aOffset < EndOffset() && endOffset.value() > mStart;
+    }
+    LayoutDeviceIntRect GetRect(uint32_t aOffset) const;
+    LayoutDeviceIntRect GetUnionRect(uint32_t aOffset, uint32_t aLength) const;
+    LayoutDeviceIntRect GetUnionRectAsFarAsPossible(
+        uint32_t aOffset, uint32_t aLength, bool aRoundToExistingOffset) const;
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const TextRectArray& aTextRectArray) {
+      aStream << "{ mStart=" << aTextRectArray.mStart
+              << ", mRects={ Length()=" << aTextRectArray.Length();
+      if (aTextRectArray.HasRects()) {
+        aStream << ", Elements()=[ ";
+        static constexpr uint32_t kMaxPrintRects = 4;
+        const uint32_t kFirstHalf = aTextRectArray.Length() <= kMaxPrintRects
+                                        ? UINT32_MAX
+                                        : (kMaxPrintRects + 1) / 2;
+        const uint32_t kSecondHalf =
+            aTextRectArray.Length() <= kMaxPrintRects ? 0 : kMaxPrintRects / 2;
+        for (uint32_t i = 0; i < aTextRectArray.Length(); i++) {
+          if (i > 0) {
+            aStream << ", ";
+          }
+          aStream << ToString(aTextRectArray.mRects[i]).c_str();
+          if (i + 1 == kFirstHalf) {
+            aStream << " ...";
+            i = aTextRectArray.Length() - kSecondHalf - 1;
+          }
+        }
+      }
+      return aStream << " ] } }";
+    }
+
+   private:
+    // For ParamTraits<TextRectArray>
+    TextRectArray() = default;
+
+    friend struct IPC::ParamTraits<ContentCache::TextRectArray>;
+    ALLOW_DEPRECATED_READPARAM
+  };
+  Maybe<TextRectArray> mTextRectArray;
+  Maybe<TextRectArray> mLastCommitStringTextRectArray;
+
+  LayoutDeviceIntRect mEditorRect;
+
+  friend class ContentCacheInParent;
+  friend struct IPC::ParamTraits<ContentCache>;
+  friend struct IPC::ParamTraits<ContentCache::Selection>;
+  friend struct IPC::ParamTraits<ContentCache::Caret>;
+  friend struct IPC::ParamTraits<ContentCache::TextRectArray>;
+  friend std::ostream& operator<<(
+      std::ostream& aStream,
+      const Selection& aSelection);  // For e(Prev|Next)CharRect
+  ALLOW_DEPRECATED_READPARAM
+};
+
+class ContentCacheInChild final : public ContentCache {
+ public:
+  ContentCacheInChild() = default;
+
+  /**
+   * Called when composition event will be dispatched in this process from
+   * PuppetWidget.
+   */
+  void OnCompositionEvent(const WidgetCompositionEvent& aCompositionEvent);
+
+  /**
+   * When IME loses focus, this should be called and making this forget the
+   * content for reducing footprint.
+   */
+  void Clear();
+
+  /**
+   * Cache*() retrieves the latest content information and store them.
+   * Be aware, CacheSelection() calls CacheCaretAndTextRects(),
+   * CacheCaretAndTextRects() calls CacheCaret() and CacheTextRects(), and
+   * CacheText() calls CacheSelection().  So, related data is also retrieved
+   * automatically.
+   */
+  bool CacheEditorRect(nsIWidget* aWidget,
+                       const IMENotification* aNotification = nullptr);
+  bool CacheCaretAndTextRects(nsIWidget* aWidget,
+                              const IMENotification* aNotification = nullptr);
+  bool CacheText(nsIWidget* aWidget,
+                 const IMENotification* aNotification = nullptr);
+
+  bool CacheAll(nsIWidget* aWidget,
+                const IMENotification* aNotification = nullptr);
+
+  /**
+   * SetSelection() modifies selection with specified raw data. And also this
+   * tries to retrieve text rects too.
+   *
+   * @return true if the selection is cached.  Otherwise, false.
+   */
+  [[nodiscard]] bool SetSelection(
+      nsIWidget* aWidget,
+      const IMENotification::SelectionChangeDataBase& aSelectionChangeData);
+
+ private:
+  bool QueryCharRect(nsIWidget* aWidget, uint32_t aOffset,
+                     LayoutDeviceIntRect& aCharRect) const;
+  bool QueryCharRectArray(nsIWidget* aWidget, uint32_t aOffset,
+                          uint32_t aLength, RectArray& aCharRectArray) const;
+  bool CacheSelection(nsIWidget* aWidget,
+                      const IMENotification* aNotification = nullptr);
+  bool CacheCaret(nsIWidget* aWidget,
+                  const IMENotification* aNotification = nullptr);
+  bool CacheTextRects(nsIWidget* aWidget,
+                      const IMENotification* aNotification = nullptr);
+
+  // Once composition is committed, all of the commit string may be composed
+  // again by Kakutei-Undo of Japanese IME.  Therefore, we need to keep
+  // storing the last composition start to cache all character rects of the
+  // last commit string.
+  Maybe<OffsetAndData<uint32_t>> mLastCommit;
+};
+
+class ContentCacheInParent final : public ContentCache {
+ public:
+  ContentCacheInParent() = delete;
+  explicit ContentCacheInParent(dom::BrowserParent& aBrowserParent);
+
+  /**
+   * AssignContent() is called when BrowserParent receives ContentCache from
+   * the content process.  This doesn't copy composition information because
+   * it's managed by BrowserParent itself.
+   */
+  void AssignContent(const ContentCache& aOther, nsIWidget* aWidget,
+                     const IMENotification* aNotification = nullptr);
+
+  /**
+   * HandleQueryContentEvent() sets content data to aEvent.mReply.
+   *
+   * For eQuerySelectedText, fail if the cache doesn't contain the whole
+   *  selected range. (This shouldn't happen because PuppetWidget should have
+   *  already sent the whole selection.)
+   *
+   * For eQueryTextContent, fail only if the cache doesn't overlap with
+   *  the queried range. Note the difference from above. We use
+   *  this behavior because a normal eQueryTextContent event is allowed to
+   *  have out-of-bounds offsets, so that widget can request content without
+   *  knowing the exact length of text. It's up to widget to handle cases when
+   *  the returned offset/length are different from the queried offset/length.
+   *
+   * For eQueryTextRect, fail if cached offset/length aren't equals to input.
+   *   Cocoa widget always queries selected offset, so it works on it.
+   *
+   * For eQueryCaretRect, fail if cached offset isn't equals to input
+   *
+   * For eQueryEditorRect, always success
+   */
+  bool HandleQueryContentEvent(WidgetQueryContentEvent& aEvent,
+                               nsIWidget* aWidget) const;
+
+  /**
+   * OnCompositionEvent() should be called before sending composition string.
+   * This returns true if the event should be sent.  Otherwise, false.
+   */
+  bool OnCompositionEvent(const WidgetCompositionEvent& aCompositionEvent);
+
+  /**
+   * OnSelectionEvent() should be called before sending selection event.
+   */
+  void OnSelectionEvent(const WidgetSelectionEvent& aSelectionEvent);
+
+  /**
+   * OnEventNeedingAckHandled() should be called after the child process
+   * handles a sent event which needs acknowledging.
+   *
+   * WARNING: This may send notifications to IME.  That might cause destroying
+   *          BrowserParent or aWidget.  Therefore, the caller must not destroy
+   *          this instance during a call of this method.
+   */
+  void OnEventNeedingAckHandled(nsIWidget* aWidget, EventMessage aMessage,
+                                uint32_t aCompositionId);
+
+  /**
+   * RequestIMEToCommitComposition() requests aWidget to commit or cancel
+   * composition.  If it's handled synchronously, this returns true.
+   *
+   * @param aWidget     The widget to be requested to commit or cancel
+   *                    the composition.
+   * @param aCancel     When the caller tries to cancel the composition, true.
+   *                    Otherwise, i.e., tries to commit the composition, false.
+   * @param aCompositionId
+   *                    The composition ID which should be committed or
+   *                    canceled.
+   * @param aCommittedString    The committed string (i.e., the last data of
+   *                            dispatched composition events during requesting
+   *                            IME to commit composition.
+   * @return            Whether the composition is actually committed
+   *                    synchronously.
+   */
+  bool RequestIMEToCommitComposition(nsIWidget* aWidget, bool aCancel,
+                                     uint32_t aCompositionId,
+                                     nsAString& aCommittedString);
+
+  /**
+   * MaybeNotifyIME() may notify IME of the notification.  If child process
+   * hasn't been handled all sending events yet, this stores the notification
+   * and flush it later.
+   */
+  void MaybeNotifyIME(nsIWidget* aWidget, const IMENotification& aNotification);
+
+ private:
+  struct HandlingCompositionData;
+
+  // Return true when the widget in this process thinks that IME has
+  // composition.  So, this returns true when there is at least one handling
+  // composition data and the last handling composition has not dispatched
+  // composition commit event to the remote process yet.
+  [[nodiscard]] bool WidgetHasComposition() const {
+    return !mHandlingCompositions.IsEmpty() &&
+           !mHandlingCompositions.LastElement().mSentCommitEvent;
+  }
+
+  // Return true if there is a pending composition which has already sent
+  // a commit event to the remote process, but not yet handled by it.
+  [[nodiscard]] bool HasPendingCommit() const {
+    for (const HandlingCompositionData& data : mHandlingCompositions) {
+      if (data.mSentCommitEvent) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  // Return the number of composition events and set selection events which were
+  // sent to the remote process, but we've not verified that the remote process
+  // finished handling it.
+  [[nodiscard]] uint32_t PendingEventsNeedingAck() const {
+    uint32_t ret = mPendingSetSelectionEventNeedingAck;
+    for (const HandlingCompositionData& data : mHandlingCompositions) {
+      ret += data.mPendingEventsNeedingAck;
+    }
+    return ret;
+  }
+
+  [[nodiscard]] HandlingCompositionData* GetHandlingCompositionData(
+      uint32_t aCompositionId) {
+    for (HandlingCompositionData& data : mHandlingCompositions) {
+      if (data.mCompositionId == aCompositionId) {
+        return &data;
+      }
+    }
+    return nullptr;
+  }
+  [[nodiscard]] const HandlingCompositionData* GetHandlingCompositionData(
+      uint32_t aCompositionId) const {
+    return const_cast<ContentCacheInParent*>(this)->GetHandlingCompositionData(
+        aCompositionId);
+  }
+
+  IMENotification mPendingSelectionChange;
+  IMENotification mPendingTextChange;
+  IMENotification mPendingLayoutChange;
+  IMENotification mPendingCompositionUpdate;
+
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  // Log of event messages to be output to crash report.
+  nsTArray<EventMessage> mDispatchedEventMessages;
+  nsTArray<EventMessage> mReceivedEventMessages;
+  // Log of RequestIMEToCommitComposition() in the last 2 compositions.
+  enum class RequestIMEToCommitCompositionResult : uint8_t {
+    eToOldCompositionReceived,
+    eToUnknownCompositionReceived,
+    eToCommittedCompositionReceived,
+    eReceivedAfterBrowserParentBlur,
+    eReceivedButNoTextComposition,
+    eReceivedButForDifferentTextComposition,
+    eHandledAsynchronously,
+    eHandledSynchronously,
+  };
+  const char* ToReadableText(
+      RequestIMEToCommitCompositionResult aResult) const {
+    switch (aResult) {
+      case RequestIMEToCommitCompositionResult::eToOldCompositionReceived:
+        return "Commit request is not handled because it's for "
+               "older composition";
+      case RequestIMEToCommitCompositionResult::eToUnknownCompositionReceived:
+        return "Commit request is not handled because it's for "
+               "unknown composition";
+      case RequestIMEToCommitCompositionResult::eToCommittedCompositionReceived:
+        return "Commit request is not handled because BrowserParent has "
+               "already "
+               "sent commit event for the composition";
+      case RequestIMEToCommitCompositionResult::eReceivedAfterBrowserParentBlur:
+        return "Commit request is handled with stored composition string "
+               "because BrowserParent has already lost focus";
+      case RequestIMEToCommitCompositionResult::eReceivedButNoTextComposition:
+        return "Commit request is not handled because there is no "
+               "TextComposition instance";
+      case RequestIMEToCommitCompositionResult::
+          eReceivedButForDifferentTextComposition:
+        return "Commit request is handled with stored composition string "
+               "because new TextComposition is active";
+      case RequestIMEToCommitCompositionResult::eHandledAsynchronously:
+        return "Commit request is handled but IME doesn't commit current "
+               "composition synchronously";
+      case RequestIMEToCommitCompositionResult::eHandledSynchronously:
+        return "Commit request is handled synchronously";
+      default:
+        return "Unknown reason";
+    }
+  }
+  nsTArray<RequestIMEToCommitCompositionResult>
+      mRequestIMEToCommitCompositionResults;
+#endif  // MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
+  // Stores pending compositions (meaning eCompositionStart was dispatched, but
+  // eCompositionCommit(AsIs) has not been handled by the remote process yet).
+  struct HandlingCompositionData {
+    // The lasted composition string which was sent to the remote process.
+    nsString mCompositionString;
+    // The composition ID of a handling composition with the instance.
+    uint32_t mCompositionId;
+    // Increased when sending composition events and decreased when the
+    // remote process finished handling the events.
+    uint32_t mPendingEventsNeedingAck = 0u;
+    // true if eCompositionCommit(AsIs) has already been sent to the remote
+    // process.
+    bool mSentCommitEvent = false;
+
+    explicit HandlingCompositionData(uint32_t aCompositionId)
+        : mCompositionId(aCompositionId) {}
+  };
+  AutoTArray<HandlingCompositionData, 2> mHandlingCompositions;
+
+  // mBrowserParent is owner of the instance.
+  dom::BrowserParent& MOZ_NON_OWNING_REF mBrowserParent;
+  // This is not nullptr only while the instance is requesting IME to
+  // composition.  Then, data value of dispatched composition events should
+  // be stored into the instance.
+  nsAString* mCommitStringByRequest;
+  // mCompositionStartInChild stores current composition start offset in the
+  // remote process.
+  Maybe<uint32_t> mCompositionStartInChild;
+  // Increased when sending eSetSelection events and decreased when the remote
+  // process finished handling the events.  Note that eSetSelection may be
+  // dispatched without composition.  Therefore, we need to count it with this.
+  uint32_t mPendingSetSelectionEventNeedingAck = 0u;
+  // mPendingCommitLength is commit string length of the first pending
+  // composition.  This is used by relative offset query events when querying
+  // new composition start offset.
+  // Note that when mHandlingCompositions has 2 or more elements, i.e., there
+  // are 2 or more pending compositions, this cache won't be used because in
+  // such case, anyway ContentCacheInParent cannot return proper character rect.
+  uint32_t mPendingCommitLength;
+  // mIsChildIgnoringCompositionEvents is set to true if the child process
+  // requests commit composition whose commit has already been sent to it.
+  // Then, set to false when the child process ignores the commit event.
+  bool mIsChildIgnoringCompositionEvents;
+
+  /**
+   * When following methods' aRoundToExistingOffset is true, even if specified
+   * offset or range is out of bounds, the result is computed with the existing
+   * cache forcibly.
+   */
+  bool GetCaretRect(uint32_t aOffset, bool aRoundToExistingOffset,
+                    LayoutDeviceIntRect& aCaretRect) const;
+  bool GetTextRect(uint32_t aOffset, bool aRoundToExistingOffset,
+                   LayoutDeviceIntRect& aTextRect) const;
+  bool GetUnionTextRects(uint32_t aOffset, uint32_t aLength,
+                         bool aRoundToExistingOffset,
+                         LayoutDeviceIntRect& aUnionTextRect) const;
+
+  void FlushPendingNotifications(nsIWidget* aWidget);
+
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  /**
+   * Remove unnecessary messages from mDispatchedEventMessages and
+   * mReceivedEventMessages.
+   */
+  void RemoveUnnecessaryEventMessageLog();
+
+  /**
+   * Append event message log to aLog.
+   */
+  void AppendEventMessageLog(nsACString& aLog) const;
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_ContentCache_h