From b0b3b72fbd6f14a0d0ba4193c2327ee995b1f7cb Mon Sep 17 00:00:00 2001
From: Mats Palmgren <matspal@gmail.com>
Date: Fri, 26 Apr 2013 10:49:07 +0200
Subject: [PATCH] Bug 861643 - nsFirstLineFrame continuations should fixup its
 style context in Init instead of Reflow.  r=bzbarsky

---
 layout/generic/nsInlineFrame.cpp | 56 +++++++++++++++++---------------
 layout/generic/nsInlineFrame.h   |  2 ++
 2 files changed, 31 insertions(+), 27 deletions(-)

diff --git a/layout/generic/nsInlineFrame.cpp b/layout/generic/nsInlineFrame.cpp
index c842367523d3..c6f905d9e0b5 100644
--- a/layout/generic/nsInlineFrame.cpp
+++ b/layout/generic/nsInlineFrame.cpp
@@ -938,6 +938,35 @@ NS_NewFirstLineFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 
 NS_IMPL_FRAMEARENA_HELPERS(nsFirstLineFrame)
 
+void
+nsFirstLineFrame::Init(nsIContent* aContent, nsIFrame* aParent,
+                       nsIFrame* aPrevInFlow)
+{
+  nsInlineFrame::Init(aContent, aParent, aPrevInFlow);
+  if (!aPrevInFlow) {
+    MOZ_ASSERT(StyleContext()->GetPseudo() == nsCSSPseudoElements::firstLine);
+    return;
+  }
+
+  // This frame is a continuation - fixup the style context if aPrevInFlow
+  // is the first-in-flow (the only one with a ::first-line pseudo).
+  if (aPrevInFlow->StyleContext()->GetPseudo() == nsCSSPseudoElements::firstLine) {
+    MOZ_ASSERT(GetFirstInFlow() == aPrevInFlow);
+    // Create a new style context that is a child of the parent
+    // style context thus removing the ::first-line style. This way
+    // we behave as if an anonymous (unstyled) span was the child
+    // of the parent frame.
+    nsStyleContext* parentContext = aParent->StyleContext();
+    nsRefPtr<nsStyleContext> newSC = PresContext()->StyleSet()->
+      ResolveAnonymousBoxStyle(nsCSSAnonBoxes::mozLineFrame, parentContext);
+    SetStyleContext(newSC);
+  } else {
+    MOZ_ASSERT(GetFirstInFlow() != aPrevInFlow);
+    MOZ_ASSERT(aPrevInFlow->StyleContext()->GetPseudo() ==
+                 nsCSSAnonBoxes::mozLineFrame);
+  }
+}
+
 #ifdef DEBUG
 NS_IMETHODIMP
 nsFirstLineFrame::GetFrameName(nsAString& aResult) const
@@ -1041,33 +1070,6 @@ nsFirstLineFrame::Reflow(nsPresContext* aPresContext,
     }
     irs.mPrevFrame = nullptr;
   }
-  else {
-// XXX do this in the Init method instead
-    // For continuations, we need to check and see if our style
-    // context is right. If its the same as the first-in-flow, then
-    // we need to fix it up (that way :first-line style doesn't leak
-    // into this continuation since we aren't the first line).
-    nsFirstLineFrame* first = (nsFirstLineFrame*) GetFirstInFlow();
-    if (mStyleContext == first->mStyleContext) {
-      // Fixup our style context and our children. First get the
-      // proper parent context.
-      nsStyleContext* parentContext = first->GetParent()->StyleContext();
-      // Create a new style context that is a child of the parent
-      // style context thus removing the :first-line style. This way
-      // we behave as if an anonymous (unstyled) span was the child
-      // of the parent frame.
-      nsRefPtr<nsStyleContext> newSC;
-      newSC = aPresContext->StyleSet()->
-        ResolveAnonymousBoxStyle(nsCSSAnonBoxes::mozLineFrame, parentContext);
-      if (newSC) {
-        // Switch to the new style context.
-        SetStyleContext(newSC);
-
-        // Re-resolve all children
-        ReparentChildListStyle(aPresContext, mFrames, this);
-      }
-    }
-  }
 
   NS_ASSERTION(!aReflowState.mLineLayout->GetInFirstLine(),
                "Nested first-line frames? BOGUS");
diff --git a/layout/generic/nsInlineFrame.h b/layout/generic/nsInlineFrame.h
index 937f1b0a0d5c..e0ecbc2ad88b 100644
--- a/layout/generic/nsInlineFrame.h
+++ b/layout/generic/nsInlineFrame.h
@@ -192,6 +192,8 @@ public:
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus& aStatus) MOZ_OVERRIDE;
 
+  virtual void Init(nsIContent* aContent, nsIFrame* aParent,
+                    nsIFrame* aPrevInFlow) MOZ_OVERRIDE;
   virtual void PullOverflowsFromPrevInFlow() MOZ_OVERRIDE;
 
 protected: