Optimize layout/repaint on FrameView resize

Source/core/rendering/RenderView.h

Index: Source/core/rendering/RenderView.h
diff --git a/Source/core/rendering/RenderView.h b/Source/core/rendering/RenderView.h
index a3b2e9dce17c16b03dc51b3f84d22b126735dcfa..118cc95f98a0448a165749a31dcc390580a22b94 100644
--- a/Source/core/rendering/RenderView.h
+++ b/Source/core/rendering/RenderView.h
@@ -133,8 +133,6 @@ public:
     }
 #endif
 
-    bool doingFullRepaint() const { return m_frameView->needsFullRepaint(); }
-
     // Subtree push
     void pushLayoutState(RenderObject&);
 
@@ -218,18 +216,10 @@ private:
     bool rootFillsViewportBackground(RenderBox* rootBox) const;
 
     // These functions may only be accessed by LayoutStateMaintainer.
-    bool pushLayoutState(RenderBox& renderer, const LayoutSize& offset, LayoutUnit pageHeight = 0, bool pageHeightChanged = false, ColumnInfo* colInfo = 0)
+    void pushLayoutState(RenderBox& renderer, const LayoutSize& offset, LayoutUnit pageHeight = 0, bool pageHeightChanged = false, ColumnInfo* colInfo = 0)
     {
-        // We push LayoutState even if layoutState is disabled because it stores layoutDelta too.
-        if (!doingFullRepaint() || m_layoutState->isPaginated() || renderer.hasColumns() || renderer.flowThreadContainingBlock()
-            || (renderer.isRenderBlock() && toRenderBlock(renderer).shapeInsideInfo())
-            || (m_layoutState->shapeInsideInfo() && renderer.isRenderBlock() && !toRenderBlock(renderer).allowsShapeInsideInfoSharing(&m_layoutState->shapeInsideInfo()->owner()))
-            ) {
-            pushLayoutStateForCurrentFlowThread(renderer);
-            m_layoutState = new LayoutState(m_layoutState, renderer, offset, pageHeight, pageHeightChanged, colInfo);
-            return true;
-        }
-        return false;
+        pushLayoutStateForCurrentFlowThread(renderer);
+        m_layoutState = new LayoutState(m_layoutState, renderer, offset, pageHeight, pageHeightChanged, colInfo);
     }
 
     void layoutContent(const LayoutState&);
@@ -283,7 +273,6 @@ public:
         , m_disabled(root.shouldDisableLayoutState())
         , m_didStart(false)
         , m_didEnd(false)
-        , m_didCreateLayoutState(false)
     {
         push(root, offset, pageHeight, pageHeightChanged, colInfo);
     }
@@ -294,7 +283,6 @@ public:
         , m_disabled(false)
         , m_didStart(false)
         , m_didEnd(false)
-        , m_didCreateLayoutState(false)
     {
     }
 
@@ -307,8 +295,8 @@ public:
     {
         ASSERT(!m_didStart);
         // We push state even if disabled, because we still need to store layoutDelta
-        m_didCreateLayoutState = m_view.pushLayoutState(root, offset, pageHeight, pageHeightChanged, colInfo);
-        if (m_disabled && m_didCreateLayoutState)
+        m_view.pushLayoutState(root, offset, pageHeight, pageHeightChanged, colInfo);
+        if (m_disabled)
             m_view.disableLayoutState();
         m_didStart = true;
     }
@@ -317,11 +305,9 @@ public:
     {
         if (m_didStart) {
             ASSERT(!m_didEnd);
-            if (m_didCreateLayoutState) {
-                m_view.popLayoutState();
-                if (m_disabled)
-                    m_view.enableLayoutState();
-            }
+            m_view.popLayoutState();
+            if (m_disabled)
+                m_view.enableLayoutState();
 
             m_didEnd = true;
         }
@@ -334,7 +320,6 @@ private:
     bool m_disabled : 1;        // true if the offset and clip part of layoutState is disabled
     bool m_didStart : 1;        // true if we did a push or disable
     bool m_didEnd : 1;          // true if we popped or re-enabled
-    bool m_didCreateLayoutState : 1; // true if we actually made a layout state.
 };
 
 class LayoutStateDisabler {