Keep track of multiple layout roots

Source/core/frame/FrameView.h

Index: Source/core/frame/FrameView.h
diff --git a/Source/core/frame/FrameView.h b/Source/core/frame/FrameView.h
index ddda79956886827b54914f5e4b2ef74059285125..4c9ad492e17caad2bdc35ab0d210bdce9612d0f7 100644
--- a/Source/core/frame/FrameView.h
+++ b/Source/core/frame/FrameView.h
@@ -102,10 +102,12 @@ public:
     bool layoutPending() const;
     bool isInPerformLayout() const;
 
-    LayoutObject* layoutRoot(bool onlyDuringLayout = false) const;
-    void clearLayoutSubtreeRoot() { m_layoutSubtreeRoot = nullptr; }
+    bool isLayoutRoot(const LayoutObject*) const;

[esprehn, 2015/02/24 02:31:32]

reference.

+    void clearLayoutSubtreeRoot(const LayoutObject*);
     int layoutCount() const { return m_layoutCount; }
 
+    void countObjectsNeedingLayout(unsigned& needsLayoutObjects, unsigned& totalObjects, bool& isPartial);

[esprehn, 2015/02/24 02:31:32]

This should really use a struct, but we can fix that later.

+
     bool needsLayout() const;
     void setNeedsLayout();
 
@@ -326,7 +328,7 @@ public:
     // FIXME: This should probably be renamed as the 'inSubtreeLayout' parameter
     // passed around the FrameView layout methods can be true while this returns
     // false.
-    bool isSubtreeLayout() const { return !!m_layoutSubtreeRoot; }
+    bool isSubtreeLayout() const { return m_isSubtreeLayout; }
 
     // Sets the tickmarks for the FrameView, overriding the default behavior
     // which is to display the tickmarks corresponding to find results.
@@ -602,6 +604,8 @@ private:
     void reset();
     void init();
 
+    void clearLayoutSubtreeRootsAndMarkContainingBlocks();
+
     // Called when our frame rect changes (or the rect/scroll position of an ancestor changes).
     virtual void frameRectsChanged() override;
 
@@ -615,14 +619,12 @@ private:
     void updateCounters();
     void forceLayoutParentViewIfNeeded();
     void performPreLayoutTasks();
-    void performLayout(LayoutObject* rootForThisLayout, bool inSubtreeLayout);
+    void performLayout(bool inSubtreeLayout);
     void scheduleOrPerformPostLayoutTasks();
     void performPostLayoutTasks();
 
     void invalidateTreeIfNeeded();
 
-    void gatherDebugLayoutRects(LayoutObject* layoutRoot);
-
     DocumentLifecycle& lifecycle() const;
 
     void contentRectangleForPaintInvalidation(const IntRect&);
@@ -719,7 +721,8 @@ private:
     unsigned m_slowRepaintObjectCount;
 
     bool m_hasPendingLayout;
-    LayoutObject* m_layoutSubtreeRoot;
+    HashSet<LayoutObject*> m_layoutSubtreeRoots;
+    bool m_isSubtreeLayout;

[esprehn, 2015/02/24 02:31:32]

It seems like we should be able to get rid of this bool, either the HashSet is
non-empty and it's a subtree layout or it's a full layout. The bool is just a
proxy for !isEmpty().

 
     bool m_layoutSchedulingEnabled;
     bool m_inPerformLayout;