diff --git a/widget/ContentCache.cpp b/widget/ContentCache.cpp
index 9b2d0da27d33..74cd2942479b 100644
--- a/widget/ContentCache.cpp
+++ b/widget/ContentCache.cpp
@@ -510,7 +510,7 @@ ContentCacheInParent::ContentCacheInParent()
   : ContentCache()
   , mCommitStringByRequest(nullptr)
   , mPendingEventsNeedingAck(0)
-  , mIsComposing(false)
+  , mWidgetHasComposition(false)
 {
 }
 
@@ -527,7 +527,7 @@ ContentCacheInParent::AssignContent(const ContentCache& aOther,
   mTextRectArray = aOther.mTextRectArray;
   mEditorRect = aOther.mEditorRect;
 
-  if (mIsComposing) {
+  if (mWidgetHasComposition) {
     NS_WARNING_ASSERTION(mCompositionStart != UINT32_MAX, "mCompositionStart");
     IMEStateManager::MaybeStartOffsetUpdatedInChild(aWidget, mCompositionStart);
   } else {
@@ -541,8 +541,8 @@ ContentCacheInParent::AssignContent(const ContentCache& aOther,
      "mAnchorCharRects[ePrevCharRect]=%s, mFocusCharRects[eNextCharRect]=%s, "
      "mFocusCharRects[ePrevCharRect]=%s, mRect=%s }, "
      "mFirstCharRect=%s, mCaret={ mOffset=%u, mRect=%s }, mTextRectArray={ "
-     "mStart=%u, mRects.Length()=%u }, mIsComposing=%s, mCompositionStart=%u, "
-     "mEditorRect=%s",
+     "mStart=%u, mRects.Length()=%u }, mWidgetHasComposition=%s, "
+     "mCompositionStart=%u, mEditorRect=%s",
      this, GetNotificationName(aNotification),
      mText.Length(), mSelection.mAnchor, mSelection.mFocus,
      GetWritingModeName(mSelection.mWritingMode).get(),
@@ -552,7 +552,7 @@ ContentCacheInParent::AssignContent(const ContentCache& aOther,
      GetRectText(mSelection.mFocusCharRects[ePrevCharRect]).get(),
      GetRectText(mSelection.mRect).get(), GetRectText(mFirstCharRect).get(),
      mCaret.mOffset, GetRectText(mCaret.mRect).get(), mTextRectArray.mStart,
-     mTextRectArray.mRects.Length(), GetBoolName(mIsComposing),
+     mTextRectArray.mRects.Length(), GetBoolName(mWidgetHasComposition),
      mCompositionStart, GetRectText(mEditorRect).get()));
 }
 
@@ -601,7 +601,7 @@ ContentCacheInParent::HandleQueryContentEvent(WidgetQueryContentEvent& aEvent,
            aEvent.mInput.mLength));
         return false;
       }
-    } else if (mIsComposing) {
+    } else if (mWidgetHasComposition) {
       if (NS_WARN_IF(!aEvent.mInput.MakeOffsetAbsolute(mCompositionStart))) {
         MOZ_LOG(sContentCacheLog, LogLevel::Error,
           ("0x%p HandleQueryContentEvent(), FAILED due to "
@@ -1058,16 +1058,16 @@ ContentCacheInParent::OnCompositionEvent(const WidgetCompositionEvent& aEvent)
   MOZ_LOG(sContentCacheLog, LogLevel::Info,
     ("0x%p OnCompositionEvent(aEvent={ "
      "mMessage=%s, mData=\"%s\" (Length()=%u), mRanges->Length()=%u }), "
-     "mPendingEventsNeedingAck=%u, mIsComposing=%s, "
+     "mPendingEventsNeedingAck=%u, mWidgetHasComposition=%s, "
      "mCommitStringByRequest=0x%p",
      this, ToChar(aEvent.mMessage),
      GetEscapedUTF8String(aEvent.mData).get(), aEvent.mData.Length(),
      aEvent.mRanges ? aEvent.mRanges->Length() : 0, mPendingEventsNeedingAck,
-     GetBoolName(mIsComposing), mCommitStringByRequest));
+     GetBoolName(mWidgetHasComposition), mCommitStringByRequest));
 
   // We must be able to simulate the selection because
   // we might not receive selection updates in time
-  if (!mIsComposing) {
+  if (!mWidgetHasComposition) {
     if (aEvent.mWidget && aEvent.mWidget->PluginHasFocus()) {
       // If focus is on plugin, we cannot get selection range
       mCompositionStart = 0;
@@ -1076,9 +1076,9 @@ ContentCacheInParent::OnCompositionEvent(const WidgetCompositionEvent& aEvent)
     }
   }
 
-  mIsComposing = !aEvent.CausesDOMCompositionEndEvent();
+  mWidgetHasComposition = !aEvent.CausesDOMCompositionEndEvent();
 
-  if (!mIsComposing) {
+  if (!mWidgetHasComposition) {
     mCompositionStart = UINT32_MAX;
   }
 
@@ -1108,13 +1108,13 @@ ContentCacheInParent::OnSelectionEvent(
     ("0x%p OnSelectionEvent(aEvent={ "
      "mMessage=%s, mOffset=%u, mLength=%u, mReversed=%s, "
      "mExpandToClusterBoundary=%s, mUseNativeLineBreak=%s }), "
-     "mPendingEventsNeedingAck=%u, mIsComposing=%s",
+     "mPendingEventsNeedingAck=%u, mWidgetHasComposition=%s",
      this, ToChar(aSelectionEvent.mMessage),
      aSelectionEvent.mOffset, aSelectionEvent.mLength,
      GetBoolName(aSelectionEvent.mReversed),
      GetBoolName(aSelectionEvent.mExpandToClusterBoundary),
      GetBoolName(aSelectionEvent.mUseNativeLineBreak), mPendingEventsNeedingAck,
-     GetBoolName(mIsComposing)));
+     GetBoolName(mWidgetHasComposition)));
 
   mPendingEventsNeedingAck++;
 }
@@ -1146,8 +1146,8 @@ ContentCacheInParent::RequestIMEToCommitComposition(nsIWidget* aWidget,
 {
   MOZ_LOG(sContentCacheLog, LogLevel::Info,
     ("0x%p RequestToCommitComposition(aWidget=%p, "
-     "aCancel=%s), mIsComposing=%s, mCommitStringByRequest=%p",
-     this, aWidget, GetBoolName(aCancel), GetBoolName(mIsComposing),
+     "aCancel=%s), mWidgetHasComposition=%s, mCommitStringByRequest=%p",
+     this, aWidget, GetBoolName(aCancel), GetBoolName(mWidgetHasComposition),
      mCommitStringByRequest));
 
   MOZ_ASSERT(!mCommitStringByRequest);
@@ -1170,8 +1170,8 @@ ContentCacheInParent::RequestIMEToCommitComposition(nsIWidget* aWidget,
 
   MOZ_LOG(sContentCacheLog, LogLevel::Info,
     ("  0x%p RequestToCommitComposition(), "
-     "mIsComposing=%s, the composition %s committed synchronously",
-     this, GetBoolName(mIsComposing),
+     "mWidgetHasComposition=%s, the composition %s committed synchronously",
+     this, GetBoolName(mWidgetHasComposition),
      composition->Destroyed() ? "WAS" : "has NOT been"));
 
   if (!composition->Destroyed()) {
diff --git a/widget/ContentCache.h b/widget/ContentCache.h
index 1b9ea305f67a..f3a7a3505e06 100644
--- a/widget/ContentCache.h
+++ b/widget/ContentCache.h
@@ -415,7 +415,10 @@ private:
   // process.
   uint32_t mPendingEventsNeedingAck;
 
-  bool mIsComposing;
+  // mWidgetHasComposition is true when the widget in this process thinks that
+  // IME has composition.  So, this is set to true when eCompositionStart is
+  // dispatched and set to false when eCompositionCommit(AsIs) is dispatched.
+  bool mWidgetHasComposition;
 
   /**
    * When following methods' aRoundToExistingOffset is true, even if specified