Implement transform/clip support for Android WebView.

cc/trees/layer_tree_host_common.cc

Index: cc/trees/layer_tree_host_common.cc
diff --git a/cc/trees/layer_tree_host_common.cc b/cc/trees/layer_tree_host_common.cc
index b8ab367d60755965c57d02ea1d75181810c5b816..9dc5f52ca2165c0a3ae616cc0b77825a595e12bb 100644
--- a/cc/trees/layer_tree_host_common.cc
+++ b/cc/trees/layer_tree_host_common.cc
@@ -798,6 +798,7 @@ static void CalculateDrawPropertiesInternal(
     const gfx::Transform& parent_matrix,
     const gfx::Transform& full_hierarchy_matrix,
     const gfx::Transform& current_scroll_compensation_matrix,
+    const gfx::Transform& next_sublayer_matrix,

[enne (OOO), 2013/05/29 20:34:12]

I'm always skeptical about adding more parameters to this function.  Maybe I'm
misunderstanding things, but is there a reason you can't just apply this
transform at the top of the tree?

     LayerType* current_fixed_container,
     gfx::Rect clip_rect_from_ancestor,
     gfx::Rect clip_rect_from_ancestor_in_descendant_space,
@@ -1311,6 +1312,8 @@ static void CalculateDrawPropertiesInternal(
                               -layer->anchor_point().y() * bounds.height());
   }
 
+  sublayer_matrix.PreconcatTransform(next_sublayer_matrix);
+
   LayerList& descendants =
       (layer->render_surface() ? layer->render_surface()->layer_list()
                                : *layer_list);
@@ -1337,11 +1340,13 @@ static void CalculateDrawPropertiesInternal(
     LayerType* child =
         LayerTreeHostCommon::get_child_as_raw_ptr(layer->children(), i);
     gfx::Rect drawable_content_rect_of_child_subtree;
+    gfx::Transform identity_matrix;
     CalculateDrawPropertiesInternal<LayerType, LayerList, RenderSurfaceType>(
         child,
         sublayer_matrix,
         next_hierarchy_matrix,
         next_scroll_compensation_matrix,
+        identity_matrix,
         next_fixed_container,
         clip_rect_for_subtree,
         clip_rect_for_subtree_in_descendant_space,
@@ -1551,9 +1556,10 @@ void LayerTreeHostCommon::CalculateDrawProperties(
   PreCalculateMetaInformation<Layer>(root_layer);
   CalculateDrawPropertiesInternal<Layer, LayerList, RenderSurface>(
       root_layer,
-      device_scale_transform,
       identity_matrix,
       identity_matrix,
+      identity_matrix,
+      device_scale_transform,
       NULL,
       device_viewport_rect,
       device_viewport_rect,
@@ -1581,6 +1587,7 @@ void LayerTreeHostCommon::CalculateDrawProperties(
 void LayerTreeHostCommon::CalculateDrawProperties(
     LayerImpl* root_layer,
     gfx::Size device_viewport_size,
+    const gfx::Transform& device_transform,
     float device_scale_factor,
     float page_scale_factor,
     LayerImpl* page_scale_application_layer,
@@ -1590,8 +1597,6 @@ void LayerTreeHostCommon::CalculateDrawProperties(
     LayerImplList* render_surface_layer_list) {
   gfx::Rect total_drawable_content_rect;
   gfx::Transform identity_matrix;
-  gfx::Transform device_scale_transform;
-  device_scale_transform.Scale(device_scale_factor, device_scale_factor);
   LayerImplList dummy_layer_list;
   LayerSorter layer_sorter;
 
@@ -1609,9 +1614,10 @@ void LayerTreeHostCommon::CalculateDrawProperties(
                                   LayerImplList,
                                   RenderSurfaceImpl>(
       root_layer,
-      device_scale_transform,
       identity_matrix,
       identity_matrix,
+      identity_matrix,
+      device_transform,
       NULL,
       device_viewport_rect,
       device_viewport_rect,