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

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

Index: chrome/android/java/src/org/chromium/chrome/browser/gsa/GSAServiceClient.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/gsa/GSAServiceClient.java b/chrome/android/java/src/org/chromium/chrome/browser/gsa/GSAServiceClient.java
index 3f34f3a5ce65dfc06f89579d3670ed2a01ad0613..6983bca34a18f93d55ab23d7e46bec12c04f3fd1 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/gsa/GSAServiceClient.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/gsa/GSAServiceClient.java
@@ -53,6 +53,12 @@ public class GSAServiceClient {
     @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;
@@ -82,6 +88,8 @@ public class GSAServiceClient {
             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);