[GCM] Passing GCMClient::AccountTokenInfo list to GCMDriver

components/gcm_driver/gcm_account_mapper.h

Index: components/gcm_driver/gcm_account_mapper.h
diff --git a/components/gcm_driver/gcm_account_mapper.h b/components/gcm_driver/gcm_account_mapper.h
index 524adbdd3554546ddaab6f09fcb2e9cfd9c0b148..fd1ca640b3773f89298a234c159fd485a7920ecc 100644
--- a/components/gcm_driver/gcm_account_mapper.h
+++ b/components/gcm_driver/gcm_account_mapper.h
@@ -37,7 +37,7 @@ class GCMAccountMapper : public GCMAppHandler {
   // Called by AccountTracker, when a new list of account tokens is available.
   // This will cause a refresh of account mappings and sending updates to GCM.
   void SetAccountTokens(
-      const std::vector<GCMClient::AccountTokenInfo> account_tokens);
+      const std::vector<GCMClient::AccountTokenInfo>& account_tokens);
 
   // Implementation of GCMAppHandler:
   virtual void ShutdownHandler() OVERRIDE;