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

cc/quads/render_pass_draw_quad.h

Index: cc/quads/render_pass_draw_quad.h
diff --git a/cc/quads/render_pass_draw_quad.h b/cc/quads/render_pass_draw_quad.h
index 1f6217ddc8c65bc1a505573b849cd568a92800d3..e2a935ccc09b6e507fdf94ea45ba22dd5b7d9d9e 100644
--- a/cc/quads/render_pass_draw_quad.h
+++ b/cc/quads/render_pass_draw_quad.h
@@ -29,6 +29,7 @@ class CC_EXPORT RenderPassDrawQuad : public DrawQuad {
               const gfx::Rect& contents_changed_since_last_frame,
               const gfx::RectF& mask_uv_rect,
               const FilterOperations& filters,
+              const gfx::Vector2dF& filters_scale,
               const FilterOperations& background_filters);
 
   void SetAll(const SharedQuadState* shared_quad_state,
@@ -42,6 +43,7 @@ class CC_EXPORT RenderPassDrawQuad : public DrawQuad {
               const gfx::Rect& contents_changed_since_last_frame,
               const gfx::RectF& mask_uv_rect,
               const FilterOperations& filters,
+              const gfx::Vector2dF& filters_scale,
               const FilterOperations& background_filters);
 
   scoped_ptr<RenderPassDrawQuad> Copy(
@@ -57,6 +59,11 @@ class CC_EXPORT RenderPassDrawQuad : public DrawQuad {
   // Post-processing filters, applied to the pixels in the render pass' texture.
   FilterOperations filters;
 
+  // Scale to be applied to filter parameters for pixel-moving filters.
+  // This should include content-to-target-space scale, and device
+  // pixel ratio.
+  gfx::Vector2dF filters_scale;
+
   // Post-processing filters, applied to the pixels showing through the
   // background of the render pass, from behind it.
   FilterOperations background_filters;