Add a command-line flag to set GPU rasterization multisampling.

cc/resources/gpu_rasterizer.cc

 // Copyright 2015 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/resources/gpu_rasterizer.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/metrics/histogram.h"
@@ skipping 13 matching lines @@
 #include "third_party/skia/include/core/SkSurface.h"
 #include "third_party/skia/include/gpu/GrContext.h"
 
 namespace cc {
 
 // static
 scoped_ptr<GpuRasterizer> GpuRasterizer::Create(
     ContextProvider* context_provider,
     ResourceProvider* resource_provider,
     bool use_distance_field_text,
-    bool tile_prepare_enabled) {
-  return make_scoped_ptr<GpuRasterizer>(
-      new GpuRasterizer(context_provider, resource_provider,
-                        use_distance_field_text, tile_prepare_enabled));
+    bool tile_prepare_enabled,
+    int msaa_sample_count) {
+  return make_scoped_ptr<GpuRasterizer>(new GpuRasterizer(
+      context_provider, resource_provider, use_distance_field_text,
+      tile_prepare_enabled, msaa_sample_count));
 }
 
 GpuRasterizer::GpuRasterizer(ContextProvider* context_provider,
                              ResourceProvider* resource_provider,
                              bool use_distance_field_text,
-                             bool tile_prepare_enabled)
+                             bool tile_prepare_enabled,
+                             int msaa_sample_count)
     : context_provider_(context_provider),
       resource_provider_(resource_provider),
       use_distance_field_text_(use_distance_field_text),
-      tile_prepare_enabled_(tile_prepare_enabled) {
+      tile_prepare_enabled_(tile_prepare_enabled),
+      msaa_sample_count_(msaa_sample_count) {
   DCHECK(context_provider_);
 }
 
 GpuRasterizer::~GpuRasterizer() {
 }
 
 PrepareTilesMode GpuRasterizer::GetPrepareTilesMode() {
   return tile_prepare_enabled_ ? PrepareTilesMode::PREPARE_PRIORITIZED_TILES
                                : PrepareTilesMode::PREPARE_NONE;
 }
@@ skipping 58 matching lines @@
   DCHECK(tile->raster_source());
 
   // Turn on distance fields for layers that have ever animated.
   bool use_distance_field_text =
       use_distance_field_text_ ||
       tile->raster_source()->ShouldAttemptToUseDistanceFieldText();
   scoped_ptr<ResourceProvider::ScopedWriteLockGr> lock(
       new ResourceProvider::ScopedWriteLockGr(resource_provider_,
                                               resource->id()));
   SkSurface* sk_surface = lock->GetSkSurface(
-      use_distance_field_text, tile->raster_source()->CanUseLCDText());
+      use_distance_field_text, tile->raster_source()->CanUseLCDText(),
+      msaa_sample_count_);
 
   locks->push_back(lock.Pass());
 
   if (!sk_surface)
     return;
 
   SkRTreeFactory factory;
   SkPictureRecorder recorder;
   gfx::Size size = resource->size();
   const int flags = SkPictureRecorder::kComputeSaveLayerInfo_RecordFlag;
   skia::RefPtr<SkCanvas> canvas = skia::SharePtr(
       recorder.beginRecording(size.width(), size.height(), &factory, flags));
 
   canvas->save();
   tile->raster_source()->PlaybackToCanvas(canvas.get(), tile->content_rect(),
                                           tile->contents_scale());
   canvas->restore();
 
   // Add the canvas and recorded picture to |multi_picture_draw_|.
   skia::RefPtr<SkPicture> picture = skia::AdoptRef(recorder.endRecording());
   multi_picture_draw_.add(sk_surface->getCanvas(), picture.get());
 }
 
 }  // namespace cc