Bug 1388877. Fix insertions under a ::first-line in stylo. r=heycam

MozReview-Commit-ID: CDolJpTtGki

layout/base/nsCSSFrameConstructor.cpp

@@ -7895,11 +7895,23 @@ nsCSSFrameConstructor::ContentAppended(nsIContent* aContainer,
     PullOutCaptionFrames(frameItems, captionItems);
   }
 
+  bool dealtWithFirstLine = false;
   if (haveFirstLineStyle && parentFrame == containingBlock) {
     // It's possible that some of the new frames go into a
     // first-line frame. Look at them and see...
     AppendFirstLineFrames(state, containingBlock->GetContent(),
                           containingBlock, frameItems);
+    // That moved things into line frames as needed, reparenting their
+    // styles.  Nothing else needs to be done.
+    dealtWithFirstLine = true;
+  }
+
+  if (!dealtWithFirstLine &&
+      parentFrame->StyleContext()->HasPseudoElementData()) {
+    // parentFrame might be inside a ::first-line frame.  Check whether it is,
+    // and if so fix up our styles.
+    CheckForFirstLineInsertion(parentFrame, frameItems);
+    CheckForFirstLineInsertion(parentFrame, captionItems);
   }
 
   // Notify the parent frame passing it the list of new frames
@@ -8495,6 +8507,7 @@ nsCSSFrameConstructor::ContentRangeInserted(nsIContent* aContainer,
     prevSibling = ::FindAppendPrevSibling(insertion.mParentFrame, appendAfterFrame);
   }
 
+  bool dealtWithFirstLine = false;
   if (haveFirstLineStyle && insertion.mParentFrame == containingBlock) {
     // It's possible that the new frame goes into a first-line
     // frame. Look at it and see...
@@ -8502,17 +8515,28 @@ nsCSSFrameConstructor::ContentRangeInserted(nsIContent* aContainer,
       // Use append logic when appending
       AppendFirstLineFrames(state, containingBlock->GetContent(),
                             containingBlock, frameItems);
+      // That moved things into line frames as needed, reparenting their
+      // styles.  Nothing else needs to be done to handle ::first-line.
+      dealtWithFirstLine = true;
     }
     else {
       // Use more complicated insert logic when inserting
       // XXXbz this method is a no-op, so it's easy for the args being passed
       // here to make no sense without anyone noticing...  If it ever stops
       // being a no-op, vet them carefully!
+      // XXXbz Can this code even get hit?  I'd think/hope not, since any
+      // insert would go into an existing lineframe if we have them..
       InsertFirstLineFrames(state, container, containingBlock, &insertion.mParentFrame,
                             prevSibling, frameItems);
     }
   }
 
+  if (!dealtWithFirstLine &&
+      insertion.mParentFrame->StyleContext()->HasPseudoElementData()) {
+    CheckForFirstLineInsertion(insertion.mParentFrame, frameItems);
+    CheckForFirstLineInsertion(insertion.mParentFrame, captionItems);
+  }
+
   // We might have captions; put them into the caption list of the
   // table wrapper frame.
   if (captionItems.NotEmpty()) {
@@ -11708,6 +11732,56 @@ nsCSSFrameConstructor::InsertFirstLineFrames(
 #endif
 }
 
+void
+nsCSSFrameConstructor::CheckForFirstLineInsertion(nsIFrame* aParentFrame,
+                                                  nsFrameItems& aFrameItems)
+{
+  MOZ_ASSERT(aParentFrame->StyleContext()->HasPseudoElementData(),
+             "Why were we called?");
+
+  if (aFrameItems.IsEmpty()) {
+    // Happens often enough, with the caption stuff.  No need to do the ancestor
+    // walk here.
+    return;
+  }
+
+  class RestyleManager* restyleManager = RestyleManager();
+  if (!restyleManager->IsServo()) {
+    // Gecko's style resolution is frame-based, so already has the right styles
+    // even in the ::first-line case.
+    return;
+  }
+
+  // Check whether there's a ::first-line on the path up from aParentFrame.
+  // Note that we can't stop until we've run out of ancestors with
+  // pseudo-element data, because the first-letter might be somewhere way up the
+  // tree; in particular it might be past our containing block.
+  nsIFrame* ancestor = aParentFrame;
+  while (ancestor) {
+    if (!ancestor->StyleContext()->HasPseudoElementData()) {
+      // We know we won't find a ::first-line now.
+      return;
+    }
+
+    if (!ancestor->IsLineFrame()) {
+      ancestor = ancestor->GetParent();
+      continue;
+    }
+
+    if (!ancestor->StyleContext()->IsPseudoElement()) {
+      // This is a continuation lineframe, not the first line; no need to do
+      // anything to the styles.
+      return;
+    }
+
+    // Fix up the styles of aFrameItems for ::first-line.
+    for (nsIFrame* f : aFrameItems) {
+      restyleManager->ReparentStyleContext(f);
+    }
+    return;
+  }
+}
+
 //----------------------------------------------------------------------
 
 // First-letter support