Rename InterfaceID to ApiID and move the file.

This was originally in the proxy and had a 1:1 correspondence with an
interface. Then we reused this for other stuff and then merged some interfaces
into larger APIs (ppapi/thunk/*_api.h) so the name was no longer accurate.
It was wrong to be in the proxy directory since directories at a "lower level"
than the proxy (ppapi/shared_impl and webkit/plugins/ppapi) depended on it.

This renames to ApiID (I avoided APIID since it looks like a define) which is
the proper description of the class, and moved it to shared_impl. This fixes
the deps since there are no longer any bad dependencies on the proxy directory.

TEST=it compiles
BUG=none

Review URL: http://codereview.chromium.org/8333004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@106619 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ppapi/proxy/ppp_messaging_proxy.cc b/ppapi/proxy/ppp_messaging_proxy.cc
index 60cd8c4e..7a45fd30 100644
--- a/ppapi/proxy/ppp_messaging_proxy.cc
+++ b/ppapi/proxy/ppp_messaging_proxy.cc
@@ -30,7 +30,7 @@
   }
 
   dispatcher->Send(new PpapiMsg_PPPMessaging_HandleMessage(
-      INTERFACE_ID_PPP_MESSAGING,
+      API_ID_PPP_MESSAGING,
       instance,
       SerializedVarSendInput(dispatcher, message_data)));
 }
@@ -62,7 +62,7 @@
   static const Info info = {
     &messaging_interface,
     PPP_MESSAGING_INTERFACE,
-    INTERFACE_ID_PPP_MESSAGING,
+    API_ID_PPP_MESSAGING,
     false,
     &CreateMessagingProxy,
   };