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

content/renderer/render_thread_impl.cc

 // Copyright (c) 2012 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 "content/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <vector>
@@ skipping 568 matching lines @@
 #else
     is_lcd_text_enabled_ = true;
 #endif
   }
 
   is_gpu_rasterization_enabled_ =
       command_line.HasSwitch(switches::kEnableGpuRasterization);
   is_gpu_rasterization_forced_ =
       command_line.HasSwitch(switches::kForceGpuRasterization);
 
+  if (command_line.HasSwitch(switches::kGpuRasterizationMSAASampleCount)) {
+      std::string string_value = command_line.GetSwitchValueASCII(
+          switches::kGpuRasterizationMSAASampleCount);
+      bool parsed_msaa_sample_count =
+          base::StringToInt(string_value, &gpu_rasterization_msaa_sample_count_);

[danakj, 2015/01/26 21:04:32]

git cl format

[Stephen White, 2015/01/26 22:39:51]

Done.

+      DCHECK(parsed_msaa_sample_count) << string_value;
+      DCHECK_GT(gpu_rasterization_msaa_sample_count_, 0);
+      DCHECK_LE(gpu_rasterization_msaa_sample_count_, 16);

[danakj, 2015/01/26 21:04:32]

magic number duplication, i'd maybe not do this

[Stephen White, 2015/01/26 22:39:51]

Good idea. In fact, there's no reason for an upper max at all; Skia will just
ignore it if it's wacky. Removed everywhere.

+  } else {
+    gpu_rasterization_msaa_sample_count_ = 0;
+  }
+
   if (command_line.HasSwitch(switches::kDisableDistanceFieldText)) {
     is_distance_field_text_enabled_ = false;
   } else if (command_line.HasSwitch(switches::kEnableDistanceFieldText)) {
     is_distance_field_text_enabled_ = true;
   } else {
     is_distance_field_text_enabled_ = false;
   }
 
   // Note that under Linux, the media library will normally already have
   // been initialized by the Zygote before this instance became a Renderer.
@@ skipping 736 matching lines @@
 }
 
 bool RenderThreadImpl::IsGpuRasterizationForced() {
   return is_gpu_rasterization_forced_;
 }
 
 bool RenderThreadImpl::IsGpuRasterizationEnabled() {
   return is_gpu_rasterization_enabled_;
 }
 
+int RenderThreadImpl::GpuRasterizationMSAASampleCount() {
+  return gpu_rasterization_msaa_sample_count_;
+}
+
 bool RenderThreadImpl::IsLcdTextEnabled() {
   return is_lcd_text_enabled_;
 }
 
 bool RenderThreadImpl::IsDistanceFieldTextEnabled() {
   return is_distance_field_text_enabled_;
 }
 
 bool RenderThreadImpl::IsZeroCopyEnabled() {
   return is_zero_copy_enabled_;
@@ skipping 420 matching lines @@
   hidden_widget_count_--;
 
   if (!GetContentClient()->renderer()->RunIdleHandlerWhenWidgetsHidden()) {
     return;
   }
 
   ScheduleIdleHandler(kLongIdleHandlerDelayMs);
 }
 
 }  // namespace content