Enable by default threaded compositing on windows and FCM on mac

chrome/browser/chrome_gpu_util.cc

Index: chrome/browser/chrome_gpu_util.cc
diff --git a/chrome/browser/chrome_gpu_util.cc b/chrome/browser/chrome_gpu_util.cc
index 90efc1246768600b631690ea153dc4a5f08a06d2..90c733304d516c8586e6a6ee8c8f71d14477846e 100644
--- a/chrome/browser/chrome_gpu_util.cc
+++ b/chrome/browser/chrome_gpu_util.cc
@@ -74,7 +74,7 @@ void InitializeCompositingFieldTrial() {
   scoped_refptr<base::FieldTrial> trial(
     base::FieldTrialList::FactoryGetFieldTrial(
         content::kGpuCompositingFieldTrialName, kDivisor,
-        "disable", 2012, 12, 31, NULL));
+        "disable", 2017, 12, 31, NULL));
 
   // Produce the same result on every run of this client.
   trial->UseOneTimeRandomization();
@@ -82,6 +82,28 @@ void InitializeCompositingFieldTrial() {
   base::FieldTrial::Probability force_compositing_mode_probability = 0;
   base::FieldTrial::Probability threaded_compositing_probability = 0;
 
+  // Threaded compositing mode isn't feature complete on mac or linux yet:
+  // http://crbug.com/133602 for mac
+  // http://crbug.com/140866 for linux
+
+#if defined(OS_WIN)
+  // threaded-compositing turned on by default on Windows.
+  // (Windows XP is excluded explicitly in ShouldRunCompositingFieldTrial)
+  threaded_compositing_probability = 3;
+#elif defined(OS_MACOSX)
+  // force-compositing-mode turned on by default on mac.
+  force_compositing_mode_probability = 3;
+#elif defined(OS_LINUX)
+  chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
+  if (channel != chrome::VersionInfo::CHANNEL_STABLE &&
+      channel != chrome::VersionInfo::CHANNEL_BETA) {
+    // On channels < beta, force-compositing-mode and
+    // threaded-compositing on with 1/3 probability each.

[Nico, 2012/09/13 01:37:21]

This is gonna be hell for bug triage. What are the plans to mitigate this?

+    force_compositing_mode_probability = 1;
+    threaded_compositing_mode_probability = 1;
+  }
+#endif
+
   chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
   if (channel == chrome::VersionInfo::CHANNEL_STABLE ||
       channel == chrome::VersionInfo::CHANNEL_BETA) {