Bug 1347433 part.3 TextEventDispatcher::PendingComposition::Flush() should replace native line breakers in the composition string before dispatching composition event r=m_kato

So, finally, Flush() should replace native line breakers in the composition string before dispatching composition events.  However, if the composition string was set by Set(), i.e., it's already been replaced with native line breakers, we shouldn't try to do it again due to performance reason.  Therefore, this patch adds |mReplacedNativeLineBreakers| to manage if it's already been called.

MozReview-Commit-ID: 5Y7ULWeP153

widget/TextEventDispatcher.cpp

@@ -598,6 +598,7 @@ TextEventDispatcher::PendingComposition::Clear()
   mString.Truncate();
   mClauses = nullptr;
   mCaret.mRangeType = TextRangeType::eUninitialized;
+  mReplacedNativeLineBreakers = false;
 }
 
 void
@@ -612,6 +613,7 @@ TextEventDispatcher::PendingComposition::EnsureClauseArray()
 nsresult
 TextEventDispatcher::PendingComposition::SetString(const nsAString& aString)
 {
+  MOZ_ASSERT(!mReplacedNativeLineBreakers);
   mString = aString;
   return NS_OK;
 }
@@ -621,6 +623,8 @@ TextEventDispatcher::PendingComposition::AppendClause(
                                            uint32_t aLength,
                                            TextRangeType aTextRangeType)
 {
+  MOZ_ASSERT(!mReplacedNativeLineBreakers);
+
   if (NS_WARN_IF(!aLength)) {
     return NS_ERROR_INVALID_ARG;
   }
@@ -648,6 +652,8 @@ nsresult
 TextEventDispatcher::PendingComposition::SetCaret(uint32_t aOffset,
                                                   uint32_t aLength)
 {
+  MOZ_ASSERT(!mReplacedNativeLineBreakers);
+
   mCaret.mStartOffset = aOffset;
   mCaret.mEndOffset = mCaret.mStartOffset + aLength;
   mCaret.mRangeType = TextRangeType::eCaret;
@@ -694,6 +700,8 @@ TextEventDispatcher::PendingComposition::Set(const nsAString& aString,
 void
 TextEventDispatcher::PendingComposition::ReplaceNativeLineBreakers()
 {
+  mReplacedNativeLineBreakers = true;
+
   // If the composition string is empty, we don't need to do anything.
   if (mString.IsEmpty()) {
     return;
@@ -779,6 +787,12 @@ TextEventDispatcher::PendingComposition::Flush(
     mClauses->AppendElement(mCaret);
   }
 
+  // If the composition string is set without Set(), we need to replace native
+  // line breakers in the composition string with XP line breaker.
+  if (!mReplacedNativeLineBreakers) {
+    ReplaceNativeLineBreakers();
+  }
+
   RefPtr<TextEventDispatcher> kungFuDeathGrip(aDispatcher);
   nsCOMPtr<nsIWidget> widget(aDispatcher->mWidget);
   WidgetCompositionEvent compChangeEvent(true, eCompositionChange, widget);