cc: Add strict layer property change checking and handle bounds changes during paint.

cc/layers/tiled_layer.cc

Index: cc/layers/tiled_layer.cc
diff --git a/cc/layers/tiled_layer.cc b/cc/layers/tiled_layer.cc
index 99b44cefb8a527e13567f6208885d08800753b1d..039841bc7490f1c061a755530ede68f67c3e83b5 100644
--- a/cc/layers/tiled_layer.cc
+++ b/cc/layers/tiled_layer.cc
@@ -470,9 +470,11 @@ void TiledLayer::UpdateTileTextures(gfx::Rect paint_rect,
   // The update_rect should be in layer space. So we have to convert the
   // paint_rect from content space to layer space.
   float width_scale =
-      bounds().width() / static_cast<float>(content_bounds().width());
+      paint_properties().bounds.width() /
+      static_cast<float>(content_bounds().width());
   float height_scale =
-      bounds().height() / static_cast<float>(content_bounds().height());
+      paint_properties().bounds.height() /
+      static_cast<float>(content_bounds().height());
   update_rect_ = gfx::ScaleRect(paint_rect, width_scale, height_scale);
 
   // Calling PrepareToUpdate() calls into WebKit to paint, which may have the