android: Record the source of account change notifications from GSA.

chrome/android/java/src/org/chromium/chrome/browser/gsa/GSAServiceClient.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.gsa;
 
 import android.annotation.SuppressLint;
 import android.app.ActivityManager;
 import android.content.ComponentName;
 import android.content.Context;
@@ skipping 35 matching lines @@
     public static final int REQUEST_REGISTER_CLIENT = 2;
     public static final int RESPONSE_UPDATE_SSB = 3;
 
     public static final String KEY_GSA_STATE = "ssb_service:ssb_state";
     public static final String KEY_GSA_CONTEXT = "ssb_service:ssb_context";
     public static final String KEY_GSA_PACKAGE_NAME = "ssb_service:ssb_package_name";
 
     @VisibleForTesting
     static final int INVALID_PSS = -1;
 
+    static final String ACCOUNT_CHANGE_HISTOGRAM = "Search.GsaAccountChangeNotificationSource";
+    // For the histogram above. Append-only.
+    static final int ACCOUNT_CHANGE_SOURCE_SERVICE = 0;
+    static final int ACCOUNT_CHANGE_SOURCE_BROADCAST = 1;
+    static final int ACCOUNT_CHANGE_SOURCE_COUNT = 2;
+
     private static boolean sHasRecordedPss;
     /** Messenger to handle incoming messages from the service */
     private final Messenger mMessenger;
     private final IncomingHandler mHandler;
     private final GSAServiceConnection mConnection;
     private final GSAHelper mGsaHelper;
     private Context mContext;
     private Callback<Bundle> mOnMessageReceived;
 
     /** Messenger for communicating with service. */
     private Messenger mService;
     private ComponentName mComponentName;
 
     /**
      * Handler of incoming messages from service.
      */
     @SuppressFBWarnings("BC_IMPOSSIBLE_CAST")
     @SuppressLint("HandlerLeak")
     private class IncomingHandler extends Handler {
         @Override
         public void handleMessage(Message msg) {
             if (msg.what != RESPONSE_UPDATE_SSB) {
                 super.handleMessage(msg);
                 return;
             }
 
             if (mService == null) return;
             final Bundle bundle = (Bundle) msg.obj;
             String account = mGsaHelper.getGSAAccountFromState(bundle.getByteArray(KEY_GSA_STATE));
+            RecordHistogram.recordEnumeratedHistogram(ACCOUNT_CHANGE_HISTOGRAM,
+                    ACCOUNT_CHANGE_SOURCE_SERVICE, ACCOUNT_CHANGE_SOURCE_COUNT);
             GSAState.getInstance(mContext.getApplicationContext()).setGsaAccount(account);
             if (sHasRecordedPss) {
                 if (mOnMessageReceived != null) mOnMessageReceived.onResult(bundle);
                 return;
             }
 
             // Getting the PSS for the GSA service process can be long, don't block the UI thread on
             // that. Also, don't process the callback before the PSS is known, since the callback
             // can lead to a service disconnect, which can lead to the framework killing the
             // process. Hence an AsyncTask (long operation), and processing the callback in
@@ skipping 142 matching lines @@
                 registerClientMessage.getData().putString(
                         KEY_GSA_PACKAGE_NAME, mContext.getPackageName());
                 mService.send(registerClientMessage);
                 // Send prepare overlay message if there is a pending GSA context.
             } catch (RemoteException e) {
                 Log.w(SERVICE_CONNECTION_TAG, "GSAServiceConnection - remote call failed", e);
             }
         }
     }
 }