Mojo: add support for disallowing sync calls for a process.

base/threading/thread_restrictions.h

Index: base/threading/thread_restrictions.h
diff --git a/base/threading/thread_restrictions.h b/base/threading/thread_restrictions.h
index a8d784dcfb07b9fd6b8dc2dd79bc909e2e77f180..0c50416c92a41abb7de7433f6de82933cd72738d 100644
--- a/base/threading/thread_restrictions.h
+++ b/base/threading/thread_restrictions.h
@@ -60,11 +60,11 @@ namespace mojo {
 namespace common {
 class MessagePumpMojo;
 }
+class SyncCallRestrictions;
 }
 namespace mus {
 class CommandBufferClientImpl;
 class CommandBufferLocal;
-class GpuService;
 class GpuState;
 }
 namespace net {
@@ -212,9 +212,9 @@ class BASE_EXPORT ThreadRestrictions {
   friend class PlatformThread;
   friend class android::JavaHandlerThread;
   friend class mojo::common::MessagePumpMojo;
+  friend class mojo::SyncCallRestrictions;
   friend class mus::CommandBufferClientImpl;
   friend class mus::CommandBufferLocal;
-  friend class mus::GpuService;                   // http://crbug.com/620058
   friend class mus::GpuState;
 
   // END ALLOWED USAGE.