Implement HiDPI and pinch-zoom scaling of filter params

cc/layers/render_surface_impl.cc

Index: cc/layers/render_surface_impl.cc
diff --git a/cc/layers/render_surface_impl.cc b/cc/layers/render_surface_impl.cc
index 04a4da49c13af8d526e4f0f4fd3dfe6cf426fd41..417643c218a2f3aca493ee59e95ecd186a9fb234 100644
--- a/cc/layers/render_surface_impl.cc
+++ b/cc/layers/render_surface_impl.cc
@@ -226,6 +226,12 @@ void RenderSurfaceImpl::AppendQuads(
 
   RenderPassDrawQuad* quad =
       render_pass->CreateAndAppendDrawQuad<RenderPassDrawQuad>();
+  gfx::Transform owning_layer_to_target_scale;
+  owning_layer_to_target_scale.Scale(owning_layer_->contents_scale_x(),
+                                     owning_layer_->contents_scale_y());
+  owning_layer_to_target_scale.PreconcatTransform(

[enne (OOO), 2014/07/25 22:45:51]

Do you really need the full transform multiplication here? It seems like you
could do target_space_transform.Scale2d() and then scale by contents_scale_x/y?

[garykac, 2014/07/29 17:10:01]

Done.

+      owning_layer_->draw_properties().target_space_transform);
+  DCHECK(owning_layer_to_target_scale.IsScale2d());
   quad->SetNew(shared_quad_state,
                content_rect_,
                visible_content_rect,
@@ -235,6 +241,7 @@ void RenderSurfaceImpl::AppendQuads(
                contents_changed_since_last_frame,
                mask_uv_rect,
                owning_layer_->filters(),
+               owning_layer_to_target_scale.Scale2d(),
                owning_layer_->background_filters());
 }