Hook ANGLE_request_extension up to the passthrough cmd decoder.

gpu/command_buffer/service/context_group.cc

Index: gpu/command_buffer/service/context_group.cc
diff --git a/gpu/command_buffer/service/context_group.cc b/gpu/command_buffer/service/context_group.cc
index 6c078a45c2294f58aeb3353694f72a45a582ce91..de793240f9b33f38a63ab05d96f2103cab443c77 100644
--- a/gpu/command_buffer/service/context_group.cc
+++ b/gpu/command_buffer/service/context_group.cc
@@ -38,6 +38,8 @@ void GetIntegerv(GLenum pname, uint32_t* var) {
   *var = value;
 }
 
+}  // namespace anonymous
+
 DisallowedFeatures AdjustDisallowedFeatures(
     ContextType context_type, const DisallowedFeatures& disallowed_features) {
   DisallowedFeatures adjusted_disallowed_features = disallowed_features;
@@ -56,8 +58,6 @@ DisallowedFeatures AdjustDisallowedFeatures(
   return adjusted_disallowed_features;
 }
 
-}  // namespace anonymous
-
 ContextGroup::ContextGroup(
     const GpuPreferences& gpu_preferences,
     const scoped_refptr<MailboxManager>& mailbox_manager,