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

content/browser/gpu/compositor_util.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/browser/gpu/compositor_util.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 16 matching lines @@
 
 const char* kGpuCompositingFeatureName = "gpu_compositing";
 const char* kWebGLFeatureName = "webgl";
 const char* kRasterizationFeatureName = "rasterization";
 const char* kThreadedRasterizationFeatureName = "threaded_rasterization";
 const char* kMultipleRasterThreadsFeatureName = "multiple_raster_threads";
 
 const int kMinRasterThreads = 1;
 const int kMaxRasterThreads = 64;
 
+const int kMinMSAASampleCount = 0;
+const int kMaxMSAASampleCount = 16;
+
 struct GpuFeatureInfo {
   std::string name;
   bool blocked;
   bool disabled;
   std::string disabled_description;
   bool fallback_to_software;
 };
 
 const GpuFeatureInfo GetGpuFeatureInfo(size_t index, bool* eof) {
   const base::CommandLine& command_line =
@@ skipping 251 matching lines @@
 #if defined(OS_ANDROID)
   return false;
 #else
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
 
   return command_line.HasSwitch(switches::kUseSurfaces);
 #endif
 }
 
+int GpuRasterizationMSAASampleCount() {
+  const base::CommandLine& command_line =
+      *base::CommandLine::ForCurrentProcess();
+
+  if (!command_line.HasSwitch(switches::kGpuRasterizationMSAASampleCount))
+    return 0;
+  std::string string_value =
+      command_line.GetSwitchValueASCII(switches::kGpuRasterizationMSAASampleCount);

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

git cl format

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

Done.

+  int msaa_sample_count = 0;
+  if (base::StringToInt(string_value, &msaa_sample_count) &&
+      msaa_sample_count >= kMinMSAASampleCount &&
+      msaa_sample_count <= kMaxMSAASampleCount) {
+    return msaa_sample_count;
+  } else {
+    LOG(WARNING) << "Failed to parse switch " <<

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

DLOG?

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

TOn 2015/01/26 21:04:32, danakj wrote:
This came from ForceNumberOfRendererRasterThreads below; I've fixed both.

+        switches::kGpuRasterizationMSAASampleCount  << ": " << string_value;
+    return 0;
+  }
+}
+
 base::DictionaryValue* GetFeatureStatus() {
   GpuDataManagerImpl* manager = GpuDataManagerImpl::GetInstance();
   std::string gpu_access_blocked_reason;
   bool gpu_access_blocked =
       !manager->GpuAccessAllowed(&gpu_access_blocked_reason);
 
   base::DictionaryValue* feature_status_dict = new base::DictionaryValue();
 
   bool eof = false;
   for (size_t i = 0; !eof; ++i) {
@@ skipping 82 matching lines @@
     }
   }
   return problem_list;
 }
 
 std::vector<std::string> GetDriverBugWorkarounds() {
   return GpuDataManagerImpl::GetInstance()->GetDriverBugWorkarounds();
 }
 
 }  // namespace content