Statically enable TCM and get rid of compositing-mode-field-trials.

This is based on top of https://codereview.chromium.org/27197009/

BUG=302738, 233830, 306557

Originally Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=229806
Reverted: https://src.chromium.org/viewvc/chrome?view=rev&revision=229907

Review URL: https://codereview.chromium.org/26389003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231949 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 13 insertions, 17 deletions

diff --git a/content/browser/gpu/compositor_util.cc b/content/browser/gpu/compositor_util.cc
index 263d9b5..32d5f7a 100644
--- a/content/browser/gpu/compositor_util.cc
+++ b/content/browser/gpu/compositor_util.cc
@@ -5,20 +5,13 @@
 #include "content/browser/gpu/compositor_util.h"
 
 #include "base/command_line.h"
-#include "base/metrics/field_trial.h"
+#include "base/logging.h"
 #include "build/build_config.h"
 #include "cc/base/switches.h"
 #include "content/browser/gpu/gpu_data_manager_impl.h"
-#include "content/public/common/content_constants.h"
 #include "content/public/common/content_switches.h"
 #include "gpu/config/gpu_feature_type.h"
 
-#if defined(OS_MACOSX)
-#include "base/mac/mac_util.h"
-#elif defined(OS_WIN)
-#include "base/win/windows_version.h"
-#endif
-
 namespace content {
 
 namespace {
@@ -186,7 +179,7 @@ const GpuFeatureInfo GetGpuFeatureInfo(size_t index) {
 bool CanDoAcceleratedCompositing() {
   const GpuDataManagerImpl* manager = GpuDataManagerImpl::GetInstance();
 
-  // Don't run the field trial if gpu access has been blocked or
+  // Don't use force compositing mode if gpu access has been blocked or
   // accelerated compositing is blacklisted.
   if (!manager->GpuAccessAllowed(NULL) ||
       manager->IsFeatureBlacklisted(
@@ -219,7 +212,7 @@ bool IsThreadedCompositingEnabled() {
 
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
-  // Command line switches take precedence over blacklist and field trials.
+  // Command line switches take precedence over blacklist.
   if (command_line.HasSwitch(switches::kDisableForceCompositingMode) ||
       command_line.HasSwitch(switches::kDisableThreadedCompositing)) {
     return false;
@@ -230,10 +223,14 @@ bool IsThreadedCompositingEnabled() {
   if (!CanDoAcceleratedCompositing() || IsForceCompositingModeBlacklisted())
     return false;
 
-  base::FieldTrial* trial =
-      base::FieldTrialList::Find(kGpuCompositingFieldTrialName);
-  return trial &&
-         trial->group_name() == kGpuCompositingFieldTrialThreadEnabledName;
+#if defined(OS_MACOSX) || defined(OS_WIN)
+  // Windows Vista+ has been shipping with TCM enabled at 100% since M24 and
+  // Mac OSX 10.8+ since M28. The blacklist check above takes care of returning
+  // false before this hits on unsupported Win/Mac versions.
+  return true;
+#endif
+
+  return false;
 }
 
 bool IsForceCompositingModeEnabled() {
@@ -243,7 +240,7 @@ bool IsForceCompositingModeEnabled() {
 
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
-  // Command line switches take precedence over blacklisting and field trials.
+  // Command line switches take precedence over blacklisting.
   if (command_line.HasSwitch(switches::kDisableForceCompositingMode))
     return false;
   else if (command_line.HasSwitch(switches::kForceCompositingMode))
@@ -252,9 +249,8 @@ bool IsForceCompositingModeEnabled() {
   if (!CanDoAcceleratedCompositing() || IsForceCompositingModeBlacklisted())
     return false;
 
-// TODO(gab): Do the same thing for TCM above once this is stable.
 #if defined(OS_MACOSX) || defined(OS_WIN)
-  // Windows Vista+ has been shipping with FCM enabled at 100% since M24 and
+  // Windows Vista+ has been shipping with TCM enabled at 100% since M24 and
   // Mac OSX 10.8+ since M28. The blacklist check above takes care of returning
   // false before this hits on unsupported Win/Mac versions.
   return true;