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

cc/layer_tree_host_common.h

Index: cc/layer_tree_host_common.h
diff --git a/cc/layer_tree_host_common.h b/cc/layer_tree_host_common.h
index cc5e6213fc465b524ff7e88090a9488ee429a8f9..77f1839f76774e54acbd9127ddf3b40155d596f3 100644
--- a/cc/layer_tree_host_common.h
+++ b/cc/layer_tree_host_common.h
@@ -20,6 +20,9 @@ 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);