Scale the ALPHA_THRESHOLD filter's region based on the device scale factor.

cc/layers/render_surface_impl.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/render_surface_impl.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
@@ skipping 179 matching lines @@
       (!mask_layer->DrawsContent() || mask_layer->bounds().IsEmpty()))
     mask_layer = NULL;
 
   if (!mask_layer && for_replica) {
     mask_layer = owning_layer_->replica_layer()->mask_layer();
     if (mask_layer &&
         (!mask_layer->DrawsContent() || mask_layer->bounds().IsEmpty()))
       mask_layer = NULL;
   }
 
+  gfx::Vector2dF owning_layer_draw_scale =
+      MathUtil::ComputeTransform2dScaleComponents(
+          owning_layer_->draw_transform(), 1.f);
   gfx::RectF mask_uv_rect(0.f, 0.f, 1.f, 1.f);
   if (mask_layer) {
-    gfx::Vector2dF owning_layer_draw_scale =
-        MathUtil::ComputeTransform2dScaleComponents(
-            owning_layer_->draw_transform(), 1.f);
     gfx::SizeF unclipped_mask_target_size = gfx::ScaleSize(
         owning_layer_->content_bounds(),
         owning_layer_draw_scale.x(),
         owning_layer_draw_scale.y());
 
     float uv_scale_x =
         content_rect_.width() / unclipped_mask_target_size.width();
     float uv_scale_y =
         content_rect_.height() / unclipped_mask_target_size.height();
 
     mask_uv_rect = gfx::RectF(
         uv_scale_x * content_rect_.x() / content_rect_.width(),
         uv_scale_y * content_rect_.y() / content_rect_.height(),
         uv_scale_x,
         uv_scale_y);
   }
 
   ResourceProvider::ResourceId mask_resource_id =
       mask_layer ? mask_layer->ContentsResourceId() : 0;
   gfx::Rect contents_changed_since_last_frame =
       ContentsChanged() ? content_rect_ : gfx::Rect();
 
+  // Calculate the total scale (including device pixel scale) for the
+  // owning_layer by combining the draw_scale and the contents_scale.
+  gfx::Vector2dF owning_layer_scale(owning_layer_draw_scale);
+  owning_layer_scale.Scale(owning_layer_->contents_scale_x(),
+                           owning_layer_->contents_scale_y());
+
   RenderPassDrawQuad* quad =
       render_pass->CreateAndAppendDrawQuad<RenderPassDrawQuad>();
   quad->SetNew(shared_quad_state,
                content_rect_,
                visible_content_rect,
                render_pass_id,
                for_replica,
                mask_resource_id,
                contents_changed_since_last_frame,
                mask_uv_rect,
                owning_layer_->filters(),
-               owning_layer_->background_filters());
+               owning_layer_->background_filters(),
+               owning_layer_scale);

[danakj, 2014/07/11 16:08:22]

let's call this "owning_layer_to_target_scale" here and everywhere else
(including comments, excluding render_surface_filters.cc and below)

[garykac, 2014/07/25 18:18:59]

Done.

 }
 
 }  // namespace cc