Get GWS ID from field trial

chrome/android/java/src/org/chromium/chrome/browser/datausage/ExternalDataUseObserver.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.datausage;
 
 import android.content.Context;
 import android.text.TextUtils;
 
 import org.chromium.base.ApplicationState;
@@ skipping 92 matching lines @@
 
     /**
      * @return the default control app package name.
      */
     protected String getDefaultControlAppPackageName() {
         return "";
     }
 
     /**
      * @return the google variation id.
+     * TODO(rajendrant): This function is unused, and should be removed.
      */
-    @CalledByNative
     protected int getGoogleVariationID() {
         return 0;
     }
 
     /**
      * Initializes the control app manager with package name of the control app.
      * @param controlAppPackageName package name of the control app. If this is empty the default
      * control app package name from {@link getDefaultControlAppPackageName} will be used.
      */
     @CalledByNative
@@ skipping 84 matching lines @@
             String[] appPackageName, String[] domainPathRegEx, String[] label);
 
     @NativeClassQualifiedName("ExternalDataUseObserverBridge")
     private native void nativeOnReportDataUseDone(
             long nativeExternalDataUseObserver, boolean success);
 
     @NativeClassQualifiedName("ExternalDataUseObserverBridge")
     private native void nativeOnControlAppInstallStateChange(
             long nativeExternalDataUseObserver, boolean isControlAppInstalled);
 }