Bug 804970, patch 4: Refactor part of RebuildAllStyleData into a helper function (slightly reordering it), so that we can share that part. r=bzbarsky

layout/base/nsCSSFrameConstructor.cpp

@@ -12101,6 +12101,24 @@ nsCSSFrameConstructor::RebuildAllStyleData(nsChangeHint aExtraHint)
 
   nsAutoScriptBlocker scriptBlocker;
 
+  nsPresContext *presContext = mPresShell->GetPresContext();
+  presContext->SetProcessingRestyles(true);
+
+  DoRebuildAllStyleData(mPendingRestyles, aExtraHint);
+
+  presContext->SetProcessingRestyles(false);
+
+  // Make sure that we process any pending animation restyles from the
+  // above style change.  Note that we can *almost* implement the above
+  // by just posting a style change -- except we really need to restyle
+  // the root frame rather than the root element's primary frame.
+  ProcessPendingRestyles();
+}
+
+void
+nsCSSFrameConstructor::DoRebuildAllStyleData(RestyleTracker& aRestyleTracker,
+                                             nsChangeHint aExtraHint)
+{
   // Tell the style set to get the old rule tree out of the way
   // so we can recalculate while maintaining rule tree immutability
   nsresult rv = mPresShell->StyleSet()->BeginReconstruct();
@@ -12108,8 +12126,6 @@ nsCSSFrameConstructor::RebuildAllStyleData(nsChangeHint aExtraHint)
     return;
   }
 
-  nsPresContext *presContext = mPresShell->GetPresContext();
-  presContext->SetProcessingRestyles(true);
   // Recalculate all of the style contexts for the document
   // Note that we can ignore the return value of ComputeStyleChangeFor
   // because we never need to reframe the root frame
@@ -12122,16 +12138,9 @@ nsCSSFrameConstructor::RebuildAllStyleData(nsChangeHint aExtraHint)
   // Note: The restyle tracker we pass in here doesn't matter.
   ComputeStyleChangeFor(mPresShell->GetRootFrame(),
                         &changeList, aExtraHint,
-                        mPendingRestyles, true);
+                        aRestyleTracker, true);
   // Process the required changes
   ProcessRestyledFrames(changeList);
-  presContext->SetProcessingRestyles(false);
-
-  // Make sure that we process any pending animation restyles from the
-  // above style change.  Note that we can *almost* implement the above
-  // by just posting a style change -- except we really need to restyle
-  // the root frame rather than the root element's primary frame.
-  ProcessPendingRestyles();
 
   // Tell the style set it's safe to destroy the old rule tree.  We
   // must do this after the ProcessRestyledFrames call in case the

layout/base/nsCSSFrameConstructor.h

@@ -276,6 +276,11 @@ public:
   // must not contain nsChangeHint_ReconstructFrame) to the root frame.
   void RebuildAllStyleData(nsChangeHint aExtraHint);
 
+  // Helper that does part of the work of RebuildAllStyleData, shared by
+  // RestyleElement for 'rem' handling.
+  void DoRebuildAllStyleData(RestyleTracker& aRestyleTracker,
+                             nsChangeHint aExtraHint);
+
   // See PostRestyleEventCommon below.
   void PostRestyleEvent(Element* aElement,
                         nsRestyleHint aRestyleHint,