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 b6f2f7f46c44171947578bf7fc520c0270d496d7..58af57d416089390d1ee6711233d12bcb87a51b2 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/string_piece.h"
 #include "base/stringprintf.h"
 #include "base/sys_info.h"
@@ -20,6 +21,7 @@
 #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 "grit/content_resources.h"
 #include "ui/base/ui_base_switches.h"
@@ -421,6 +423,12 @@ void GpuDataManagerImpl::UpdateVideoMemoryUsageStats(
                          video_memory_usage_stats);
 }
 
+// Experiment to determine whether Stage3D should be blacklisted on XP.
+bool Stage3DBlacklisted() {
+  return base::FieldTrialList::FindFullName(content::kStage3DFieldTrialName) ==
+      content::kStage3DFieldTrialBlacklistedName;
+}
+
 void GpuDataManagerImpl::UpdateBlacklistedFeatures(
     GpuFeatureType features) {
   CommandLine* command_line = CommandLine::ForCurrentProcess();
@@ -436,6 +444,9 @@ 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();