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

cc/output/gl_renderer.cc

 // Copyright 2010 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/output/gl_renderer.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <string>
@@ skipping 844 matching lines @@
   device_background_texture->Allocate(
       window_rect.size(), ResourceProvider::TextureUsageFramebuffer, RGBA_8888);
   {
     ResourceProvider::ScopedWriteLockGL lock(resource_provider_,
                                              device_background_texture->id());
     GetFramebufferTexture(
         lock.texture_id(), device_background_texture->format(), window_rect);
   }
 
   skia::RefPtr<SkImageFilter> filter = RenderSurfaceFilters::BuildImageFilter(
-      quad->background_filters, device_background_texture->size());
+      quad->background_filters, quad->scale, device_background_texture->size());
 
   SkBitmap filtered_device_background;
   if (apply_background_filters) {
     filtered_device_background =
         ApplyImageFilter(ScopedUseGrContext::Create(this, frame),
                          resource_provider_,
                          quad->rect.origin(),
                          filter.get(),
                          device_background_texture.get());
   }
@@ skipping 98 matching lines @@
       SetBlendEnabled(true);
   }
 
   // TODO(senorblanco): Cache this value so that we don't have to do it for both
   // the surface and its replica.  Apply filters to the contents texture.
   SkBitmap filter_bitmap;
   SkScalar color_matrix[20];
   bool use_color_matrix = false;
   if (!quad->filters.IsEmpty()) {
     skia::RefPtr<SkImageFilter> filter = RenderSurfaceFilters::BuildImageFilter(
-        quad->filters, contents_texture->size());
+        quad->filters, quad->scale, contents_texture->size());
     if (filter) {
       skia::RefPtr<SkColorFilter> cf;
 
       {
         SkColorFilter* colorfilter_rawptr = NULL;
         filter->asColorFilter(&colorfilter_rawptr);
         cf = skia::AdoptRef(colorfilter_rawptr);
       }
 
       if (cf && cf->asColorMatrix(color_matrix) && !filter->getInput(0)) {
@@ skipping 2170 matching lines @@
     context_support_->ScheduleOverlayPlane(
         overlay.plane_z_order,
         overlay.transform,
         pending_overlay_resources_.back()->texture_id(),
         overlay.display_rect,
         overlay.uv_rect);
   }
 }
 
 }  // namespace cc