Bug 1225018 part 1 - Trigger reflow on some text emphasis changes for line height calculation. r=dbaron

--HG--
extra : source : 96f505fe488a4345906f362beab47db5af94e894

layout/style/nsStyleStruct.cpp

@@ -3632,14 +3632,21 @@ nsChangeHint nsStyleText::CalcDifference(const nsStyleText& aOther) const
       (mTabSize != aOther.mTabSize))
     return NS_STYLE_HINT_REFLOW;
 
+  if (HasTextEmphasis() != aOther.HasTextEmphasis() ||
+      (HasTextEmphasis() &&
+       mTextEmphasisPosition != aOther.mTextEmphasisPosition)) {
+    // Text emphasis position change could affect line height calculation.
+    return nsChangeHint_AllReflowHints |
+           nsChangeHint_RepaintFrame;
+  }
+
   if (!AreShadowArraysEqual(mTextShadow, aOther.mTextShadow)) {
     return nsChangeHint_UpdateSubtreeOverflow |
            nsChangeHint_SchedulePaint |
            nsChangeHint_RepaintFrame;
   }
 
-  if (mTextEmphasisPosition != aOther.mTextEmphasisPosition ||
-      mTextEmphasisStyle != aOther.mTextEmphasisStyle ||
+  if (mTextEmphasisStyle != aOther.mTextEmphasisStyle ||
       mTextEmphasisStyleString != aOther.mTextEmphasisStyleString) {
     return nsChangeHint_UpdateOverflow |
            nsChangeHint_SchedulePaint |
@@ -3657,6 +3664,10 @@ nsChangeHint nsStyleText::CalcDifference(const nsStyleText& aOther) const
            nsChangeHint_RepaintFrame;
   }
 
+  if (mTextEmphasisPosition != aOther.mTextEmphasisPosition) {
+    return nsChangeHint_NeutralChange;
+  }
+
   return NS_STYLE_HINT_NONE;
 }