Bug 1400101 - [robocop] Find toolbar first and use it to find menu button. r=JanH,nechen

Sometimes Robocop is confused when are multiple `R.id.menu` UI components shown on screen,
one is the menu button on toolbar and otehrs are context menus on Activity Stream.

To access the menu on toolbar, a simple fix is access toolbar first and use it to find its child.

MozReview-Commit-ID: Jw4sTLeR3li

--HG--
extra : rebase_source : 337c3df3ffd36a4d26547b994aba3ce7647bafc8

mobile/android/tests/browser/robocop/src/org/mozilla/gecko/tests/components/AppMenuComponent.java

@@ -20,6 +20,7 @@ import org.mozilla.gecko.tests.UITestContext;
 import org.mozilla.gecko.tests.helpers.DeviceHelper;
 import org.mozilla.gecko.tests.helpers.RobotiumHelper;
 import org.mozilla.gecko.tests.helpers.WaitHelper;
+import org.mozilla.gecko.toolbar.BrowserToolbar;
 
 import android.text.TextUtils;
 import android.view.View;
@@ -117,7 +118,8 @@ public class AppMenuComponent extends BaseComponent {
     }
 
     private View getOverflowMenuButtonView() {
-        return mSolo.getView(R.id.menu);
+        final BrowserToolbar toolbar = (BrowserToolbar) mSolo.getView(R.id.browser_toolbar);
+        return toolbar.findViewById(R.id.menu);
     }
 
     /**