Keep the GCM data intact when the user signs out of the profile

components/gcm_driver/gcm_driver_android.cc

Index: components/gcm_driver/gcm_driver_android.cc
diff --git a/components/gcm_driver/gcm_driver_android.cc b/components/gcm_driver/gcm_driver_android.cc
index d7fc912884e2e8b066654011de0570d5c7071caa..bee1980153d078e8f7654e704594bc578aecf427 100644
--- a/components/gcm_driver/gcm_driver_android.cc
+++ b/components/gcm_driver/gcm_driver_android.cc
@@ -95,6 +95,9 @@ bool GCMDriverAndroid::RegisterBindings(JNIEnv* env) {
 void GCMDriverAndroid::OnSignedIn() {
 }
 
+void GCMDriverAndroid::OnSignedOut() {
+}
+
 void GCMDriverAndroid::Purge() {
 }