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

content/browser/gpu/compositor_util.cc

Index: content/browser/gpu/compositor_util.cc
diff --git a/content/browser/gpu/compositor_util.cc b/content/browser/gpu/compositor_util.cc
index 444f43c67acb8add4923b8c96e321c38a635b4af..37e9c571719267eb8646878241c074f077c7b6e1 100644
--- a/content/browser/gpu/compositor_util.cc
+++ b/content/browser/gpu/compositor_util.cc
@@ -34,6 +34,9 @@ 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;
@@ -305,6 +308,26 @@ bool UseSurfacesEnabled() {
 #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;