Mark layers that can use LCD text based on layer transform and opacity.

cc/layer_tree_host_common.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_COMMON_H_
 #define CC_LAYER_TREE_HOST_COMMON_H_
 
 #include "base/memory/ref_counted.h"
 #include "cc/cc_export.h"
 #include "cc/scoped_ptr_vector.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/vector2d.h"
 #include <public/WebTransformationMatrix.h>
 
 namespace cc {
 
 class LayerImpl;
 class LayerSorter;
 class Layer;
 
 class CC_EXPORT LayerTreeHostCommon {
 public:
+    // Returns the default LCD text setting.

[danakj, 2012/11/07 18:15:00]

Can we make this a LayerTreeSetting instead? Other platforms (eg highdpi ones)
will like to use this as well. That would allow chromium to set it
appropriately.

I guess leave the ifdef on the LayerTreeSetting for now, but then file a bug for
android to set the value from outside the compositor, and remove the ifdef?

[alokp, 2012/11/08 22:34:07]

Done.

+    static bool canUseLCDText();
+
     static gfx::Rect calculateVisibleRect(const gfx::Rect& targetSurfaceRect, const gfx::Rect& layerBoundRect, const WebKit::WebTransformationMatrix&);
 
     static void calculateDrawTransforms(Layer* rootLayer, const gfx::Size& deviceViewportSize, float deviceScaleFactor, float pageScaleFactor, int maxTextureSize, std::vector<scoped_refptr<Layer> >& renderSurfaceLayerList);
     static void calculateDrawTransforms(LayerImpl* rootLayer, const gfx::Size& deviceViewportSize, float deviceScaleFactor, float pageScaleFactor, LayerSorter*, int maxTextureSize, std::vector<LayerImpl*>& renderSurfaceLayerList);
 
     // Performs hit testing for a given renderSurfaceLayerList.
     static LayerImpl* findLayerThatIsHitByPoint(const gfx::PointF& screenSpacePoint, std::vector<LayerImpl*>& renderSurfaceLayerList);
 
     template<typename LayerType> static bool renderSurfaceContributesToTarget(LayerType*, int targetSurfaceLayerID);
 
@@ skipping 54 matching lines @@
     for (size_t i = 0; i < rootLayer->children().size(); ++i) {
         if (LayerType* found = findLayerInSubtree(getChildAsRawPtr(rootLayer->children(), i), layerId))
             return found;
     }
     return 0;
 }
 
 }  // namespace cc
 
 #endif  // CC_LAYER_TREE_HOST_COMMON_H_