Enable FeatureList for the GPU process.

content/browser/browser_child_process_host_impl.h

Index: content/browser/browser_child_process_host_impl.h
diff --git a/content/browser/browser_child_process_host_impl.h b/content/browser/browser_child_process_host_impl.h
index 3a798c27bbc93aeaa5d6cd15f2eb02923dcb4729..a120ad194181f991d3434eec59f67cf3ec53d07c 100644
--- a/content/browser/browser_child_process_host_impl.h
+++ b/content/browser/browser_child_process_host_impl.h
@@ -54,6 +54,11 @@ class CONTENT_EXPORT BrowserChildProcessHostImpl
   // instance.
   static void TerminateAll();
 
+  // Copies kEnableFeatures and kDisableFeatures to the command line. Generates
+  // them from the FeatureList override state, to take into account overrides
+  // from FieldTrials.
+  static void CopyFeatureAndFieldTrialFlags(base::CommandLine* cmd_line);
+
   // BrowserChildProcessHost implementation:
   bool Send(IPC::Message* message) override;
   void Launch(SandboxedProcessLauncherDelegate* delegate,