Implement hidpi and pinch-zoom scaling of filter params in cc.

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 a87d6924f6355a662cfb9161a578e39145200cf8..134e1eaa488b17106b97ebb792d3a1e6c0b68bf1 100644
--- a/cc/layers/render_surface_impl.cc
+++ b/cc/layers/render_surface_impl.cc
@@ -219,6 +219,12 @@ void RenderSurfaceImpl::AppendQuads(QuadSink* quad_sink,
       ContentsChanged() ? content_rect_ : gfx::Rect();
 
   scoped_ptr<RenderPassDrawQuad> quad = RenderPassDrawQuad::Create();
+  gfx::Transform scaleTransform;

[danakj, 2014/03/07 20:54:05]

owning_layer_to_target_transform

[Stephen White, 2014/03/07 21:54:14]

I'm gonna try just pulling out the Scale2D components directly from
target_space_transform, and just doing some multiplies, instead of a big-ol'
matmult. Let me know what you think.

[danakj, 2014/03/07 22:04:17]

Yep sounds good, and we'll have to defer that to GLRenderer I think.

+  scaleTransform.Scale(owning_layer_->contents_scale_x(),
+                       owning_layer_->contents_scale_y());
+  scaleTransform.PreconcatTransform(
+      owning_layer_->draw_properties().target_space_transform);
+  DCHECK(scaleTransform.IsScale2d());
   quad->SetNew(shared_quad_state,
                content_rect_,
                visible_content_rect,
@@ -228,7 +234,8 @@ void RenderSurfaceImpl::AppendQuads(QuadSink* quad_sink,
                contents_changed_since_last_frame,
                mask_uv_rect,
                owning_layer_->filters(),
-               owning_layer_->background_filters());
+               owning_layer_->background_filters(),
+               scaleTransform.Scale2d());
   quad_sink->Append(quad.PassAs<DrawQuad>(), append_quads_data);
 }