cc: Only allow trees created at the current viewport size to draw.

cc/layer_tree_host_impl.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_LAYER_TREE_HOST_IMPL_H_
 #define CC_LAYER_TREE_HOST_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
@@ skipping 168 matching lines @@
     LayerImpl* rootLayer() const;
     LayerImpl* rootScrollLayer() const;
     LayerImpl* currentlyScrollingLayer() const;
 
     bool visible() const { return m_visible; }
     void setVisible(bool);
 
     size_t memoryAllocationLimitBytes() const { return m_managedMemoryPolicy.bytesLimitWhenVisible; }
 
     void setViewportSize(const gfx::Size& layoutViewportSize, const gfx::Size& deviceViewportSize);
-    const gfx::Size& layoutViewportSize() const { return m_layoutViewportSize; }
+    const gfx::Size& layoutViewportSize() const;
 
     float deviceScaleFactor() const { return m_deviceScaleFactor; }
     void setDeviceScaleFactor(float);
 
     scoped_ptr<ScrollAndScaleSet> processScrollDeltas();
 
     void startPageScaleAnimation(gfx::Vector2d targetOffset, bool useAnchor, float scale, base::TimeDelta duration);
 
     bool needsAnimateLayers() const { return !m_animationRegistrar->active_animation_controllers().empty(); }
 
@@ skipping 125 matching lines @@
 
     // In impl-side painting mode, inert tree with layers that can be recycled
     // by the next sync from the main thread.
     scoped_ptr<LayerTreeImpl> m_recycleTree;
 
     bool m_didLockScrollingLayer;
     bool m_shouldBubbleScrolls;
     bool m_wheelScrolling;
     LayerTreeSettings m_settings;
     LayerTreeDebugState m_debugState;
-    gfx::Size m_layoutViewportSize;
-    gfx::Size m_deviceViewportSize;
     float m_deviceScaleFactor;
     bool m_visible;
     ManagedMemoryPolicy m_managedMemoryPolicy;
 
     bool m_pinchGestureActive;
     gfx::Point m_previousPinchAnchor;
 
     // This is set by animateLayers() and used by updateAnimationState()
     // when sending animation events to the main thread.
     base::Time m_lastAnimationTime;
@@ skipping 24 matching lines @@
     base::TimeTicks m_currentFrameTime;
 
     scoped_ptr<AnimationRegistrar> m_animationRegistrar;
 
     DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYER_TREE_HOST_IMPL_H_