[Extensions Bindings] Add a bridge to use current custom bindings

extensions/renderer/api_bindings_system.h

Index: extensions/renderer/api_bindings_system.h
diff --git a/extensions/renderer/api_bindings_system.h b/extensions/renderer/api_bindings_system.h
index e7173c4ecbf0e69e9a657bcaabacb8a575455270..11833925250f0193c4893f0453f9e9617d5f0cc5 100644
--- a/extensions/renderer/api_bindings_system.h
+++ b/extensions/renderer/api_bindings_system.h
@@ -58,7 +58,8 @@ class APIBindingsSystem {
       const std::string& api_name,
       v8::Local<v8::Context> context,
       v8::Isolate* isolate,
-      const APIBinding::AvailabilityCallback& is_available);
+      const APIBinding::AvailabilityCallback& is_available,
+      v8::Local<v8::Object>* hooks_interface_out);

[Devlin, 2016/12/16 01:55:49]

I don't particularly love this interface, but unfortunately our current bindings
rely on having the API object ready as well (even though they perhaps
shouldn't).  This was the cleanest way I could find overall, and it seems to
keep everything minimally intrusive.  But I'm open to other suggestions. :)

 
   // Responds to the request with the given |request_id|, calling the callback
   // with |response|.