Add field trial for enabling Stage3D in XP

content/browser/gpu/gpu_data_manager_impl.cc

Index: content/browser/gpu/gpu_data_manager_impl.cc
diff --git a/content/browser/gpu/gpu_data_manager_impl.cc b/content/browser/gpu/gpu_data_manager_impl.cc
index d549edf8f52267eb97f31172a31d00cc610d7b45..8f18faa4aba6f14a7265f4fa0255455eeca24a0e 100644
--- a/content/browser/gpu/gpu_data_manager_impl.cc
+++ b/content/browser/gpu/gpu_data_manager_impl.cc
@@ -8,6 +8,7 @@
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
+#include "base/metrics/field_trial.h"
 #include "base/stringprintf.h"
 #include "base/sys_info.h"
 #include "base/values.h"
@@ -19,6 +20,7 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/gpu_data_manager_observer.h"
 #include "content/public/common/content_client.h"
+#include "content/public/common/content_constants.h"
 #include "content/public/common/content_switches.h"
 #include "ui/base/ui_base_switches.h"
 #include "ui/gl/gl_implementation.h"
@@ -383,6 +385,20 @@ void GpuDataManagerImpl::UpdateVideoMemoryUsageStats(
                          video_memory_usage_stats);
 }
 
+// Experiment to determine whether Stage3D should be blacklisted on XP.
+bool Stage3DBlacklisted() {
+#if !defined(OS_WIN)
+  return false;
+#else
+  if (base::win::GetVersion() >= base::win::VERSION_VISTA)
+    return false;
+  base::FieldTrial* trial =
+      base::FieldTrialList::Find(content::kStage3DFieldTrialName);
+  return !trial ||
+      trial->group_name() == content::kStage3DFieldTrialBlacklistedName;

[Alexei Svitkine (slow), 2012/09/19 20:33:16]

Nit: You can just use:

return base::FieldTrialList::FindFullName(content::kStage3DFieldTrialName) ==
      content::kStage3DFieldTrialBlacklistedName;

If the trial doesn't exist, it will return an empty string, which wouldn't equal
your group.

+#endif
+}
+
 void GpuDataManagerImpl::UpdateBlacklistedFeatures(
     GpuFeatureType features) {
   CommandLine* command_line = CommandLine::ForCurrentProcess();
@@ -398,6 +414,9 @@ void GpuDataManagerImpl::UpdateBlacklistedFeatures(
       command_line->HasSwitch(switches::kBlacklistWebGL)) {
     flags |= content::GPU_FEATURE_TYPE_WEBGL;
   }
+  if (Stage3DBlacklisted()) {
+    flags |= content::GPU_FEATURE_TYPE_FLASH_STAGE3D;
+  }
   gpu_feature_type_ = static_cast<GpuFeatureType>(flags);
 
   EnableSoftwareRenderingIfNecessary();