Add field trial for enabling Stage3D in XP

content/browser/gpu/gpu_data_manager_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/browser/gpu/gpu_data_manager_impl.h"
 
 #include "base/bind.h"
 #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"
 #include "base/version.h"
 #include "content/browser/gpu/gpu_process_host.h"
 #include "content/browser/gpu/gpu_util.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "content/gpu/gpu_info_collector.h"
 #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"
 #include "ui/gl/gl_switches.h"
 #include "webkit/plugins/plugin_switches.h"
 
 #if defined(OS_WIN)
 #include "base/win/windows_version.h"
 #endif
 
@@ skipping 344 matching lines @@
 void GpuDataManagerImpl::NotifyGpuInfoUpdate() {
   observer_list_->Notify(&GpuDataManagerObserver::OnGpuInfoUpdate);
 }
 
 void GpuDataManagerImpl::UpdateVideoMemoryUsageStats(
     const content::GPUVideoMemoryUsageStats& video_memory_usage_stats) {
   observer_list_->Notify(&GpuDataManagerObserver::OnVideoMemoryUsageStatsUpdate,
                          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();
   int flags = features;
 
   // Force disable using the GPU for these features, even if they would
   // otherwise be allowed.
   if (card_blacklisted_ ||
       command_line->HasSwitch(switches::kBlacklistAcceleratedCompositing)) {
     flags |= content::GPU_FEATURE_TYPE_ACCELERATED_COMPOSITING;
   }
   if (card_blacklisted_ ||
       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();
 }
 
 void GpuDataManagerImpl::RegisterSwiftShaderPath(const FilePath& path) {
   swiftshader_path_ = path;
   EnableSoftwareRenderingIfNecessary();
 }
 
@@ skipping 15 matching lines @@
 
 void GpuDataManagerImpl::BlacklistCard() {
   card_blacklisted_ = true;
 
   gpu_feature_type_ = content::GPU_FEATURE_TYPE_ALL;
 
   EnableSoftwareRenderingIfNecessary();
   NotifyGpuInfoUpdate();
 }