Enable Pepper threading on canary.

content/ppapi_plugin/ppapi_thread.cc

Index: content/ppapi_plugin/ppapi_thread.cc
diff --git a/content/ppapi_plugin/ppapi_thread.cc b/content/ppapi_plugin/ppapi_thread.cc
index b3259c7703d406eed3277460892bb865ede85269..ce57fb4f768a9da48935af72b4587ba6e20c3d0a 100644
--- a/content/ppapi_plugin/ppapi_thread.cc
+++ b/content/ppapi_plugin/ppapi_thread.cc
@@ -61,8 +61,13 @@ PpapiThread::PpapiThread(const CommandLine& command_line, bool is_broker)
   globals->set_plugin_proxy_delegate(this);
   globals->set_command_line(
       command_line.GetSwitchValueASCII(switches::kPpapiFlashArgs));
-  globals->set_enable_threading(
-      command_line.HasSwitch(switches::kEnablePepperThreading));
+  if (command_line.HasSwitch(switches::kDisablePepperThreading)) {
+    globals->set_enable_threading(false);
+  } else if (command_line.HasSwitch(switches::kEnablePepperThreading)) {
+    globals->set_enable_threading(true);
+  } else {
+    globals->set_enable_threading(false);
+  }
 
   webkit_platform_support_.reset(new PpapiWebKitPlatformSupportImpl);
   WebKit::initialize(webkit_platform_support_.get());