Bug 1324618 part 8. Implement restyling for first-letter frames. r=emilio

MozReview-Commit-ID: IPUDD1Q6AFq

layout/base/nsCSSFrameConstructor.cpp

@@ -11715,7 +11715,8 @@ nsCSSFrameConstructor::CreateLetterFrame(nsContainerFrame* aBlockFrame,
   NS_ASSERTION(nsLayoutUtils::GetAsBlock(aBlockFrame),
                  "Not a block frame?");
 
-  // Get style context for the first-letter-frame
+  // Get style context for the first-letter-frame.  Keep this in sync with
+  // nsBlockFrame::UpdatePseudoElementStyles.
   nsStyleContext* parentStyleContext =
     nsFrame::CorrectStyleParentFrame(aParentFrame,
                                      nsCSSPseudoElements::firstLetter)->

layout/generic/nsBlockFrame.cpp

@@ -5625,6 +5625,46 @@ nsBlockInFlowLineIterator::nsBlockInFlowLineIterator(nsBlockFrame* aFrame,
   *aFoundValidLine = FindValidLine();
 }
 
+void
+nsBlockFrame::UpdateFirstLetterStyle(nsIFrame* aLetterFrame,
+                                     ServoRestyleState& aRestyleState)
+{
+  // Figure out what the right style parent is.  This needs to match
+  // nsCSSFrameConstructor::CreateLetterFrame.
+  nsIFrame* inFlowFrame = aLetterFrame;
+  if (inFlowFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW) {
+    inFlowFrame = inFlowFrame->GetPlaceholderFrame();
+  }
+  nsIFrame* styleParent =
+    CorrectStyleParentFrame(inFlowFrame->GetParent(),
+                            nsCSSPseudoElements::firstLetter);
+  nsStyleContext* parentStyle = styleParent->StyleContext();
+  RefPtr<nsStyleContext> firstLetterStyle =
+    aRestyleState.StyleSet()
+                 .ResolvePseudoElementStyle(mContent->AsElement(),
+                                            CSSPseudoElementType::firstLetter,
+                                            parentStyle,
+                                            nullptr);
+  // Note that we don't need to worry about changehints for the continuation
+  // styles: those will be handled by the styleParent already.
+  RefPtr<nsStyleContext> continuationStyle =
+    aRestyleState.StyleSet().ResolveStyleForFirstLetterContinuation(parentStyle);
+  UpdateStyleOfOwnedChildFrame(aLetterFrame, firstLetterStyle, aRestyleState,
+                               Some(continuationStyle.get()));
+
+  // We also want to update the style on the textframe inside the first-letter.
+  // We don't need to compute a changehint for this, though, since any changes
+  // to it are handled by the first-letter anyway.
+  nsIFrame* textFrame = aLetterFrame->PrincipalChildList().FirstChild();
+  RefPtr<nsStyleContext> firstTextStyle =
+    aRestyleState.StyleSet().ResolveStyleForText(textFrame->GetContent(),
+                                                 firstLetterStyle);
+  textFrame->SetStyleContext(firstTextStyle);
+
+  // We don't need to update style for textFrame's continuations: it's already
+  // set up to inherit from parentStyle, which is what we want.
+}
+
 static nsIFrame*
 FindChildContaining(nsBlockFrame* aFrame, nsIFrame* aFindFrame)
 {
@@ -7524,6 +7564,10 @@ nsBlockFrame::UpdatePseudoElementStyles(ServoRestyleState& aRestyleState)
       ResolveBulletStyle(type, &aRestyleState.StyleSet());
     UpdateStyleOfOwnedChildFrame(bullet, newBulletStyle, aRestyleState);
   }
+
+  if (nsIFrame* firstLetter = GetFirstLetter()) {
+    UpdateFirstLetterStyle(firstLetter, aRestyleState);
+  }
 }
 
 already_AddRefed<nsStyleContext>

layout/generic/nsBlockFrame.h

@@ -923,6 +923,10 @@ protected:
     mozilla::CSSPseudoElementType aType,
     mozilla::StyleSetHandle aStyleSet);
 
+  // Update our first-letter styles during stylo post-traversal.
+  void UpdateFirstLetterStyle(nsIFrame* aLetterFrame,
+                              mozilla::ServoRestyleState& aRestyleState);
+
 #ifdef DEBUG
   void VerifyLines(bool aFinalCheckOK);
   void VerifyOverflowSituation();