Data Saver Details IPH must only be shown for particular activity type.

The Data Saver Details in-product help should only ever be displayed in
the case of a ChromeTabbedActivity.

Additionally, not all activities in Chrome has a ToolbarManager.

Since the in-product help code uses the ToolbarManager from the current
activity on a didFinishPageLoad() event, this will lead to an NPE.

This CL ensures that we bail out early if the activity is not of the
correct type.

BUG=772556

Change-Id: I0c7dfe194625fba79ed8eadf7c1f2dd2947abc94
Reviewed-on: https://chromium-review.googlesource.com/706540
Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Tommy Nyquist <nyquist@chromium.org>
Cr-Commit-Position: refs/heads/master@{#507247}

chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java

@@ -45,6 +45,7 @@
 import org.chromium.chrome.browser.ChromeActionModeCallback;
 import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.ChromeFeatureList;
+import org.chromium.chrome.browser.ChromeTabbedActivity;
 import org.chromium.chrome.browser.ChromeVersionInfo;
 import org.chromium.chrome.browser.FrozenNativePage;
 import org.chromium.chrome.browser.IntentHandler;
@@ -1613,6 +1614,8 @@ protected void didFinishPageLoad() {
     private void maybeShowDataSaverInProductHelp(final Tracker tracker) {
         if (!tracker.shouldTriggerHelpUI(FeatureConstants.DATA_SAVER_DETAIL_FEATURE)) return;
 
+        if (!(getActivity() instanceof ChromeTabbedActivity)) return;
+
         ViewAnchoredTextBubble textBubble = new ViewAnchoredTextBubble(getActivity(),
                 getActivity().getToolbarManager().getMenuButton(),
                 R.string.iph_data_saver_detail_text,