AndroidX Webkit: add giant interstitial to testapp

No change to production, just testapp. This implements support for Giant
interstitials in the demo app by creating a partially-offscreen WebView
(it's 110% the size of the viewport in both height & width).

Bug: 124773936
Test: Manual (see uploaded video)
Change-Id: Icc9c2b4aa54504e54b573898dc975e04c6fa63bc

diff --git a/webkit/integration-tests/testapp/src/main/java/com/example/androidx/webkit/SafeBrowsingActivity.java b/webkit/integration-tests/testapp/src/main/java/com/example/androidx/webkit/SafeBrowsingActivity.java
index 929f0a9..c3495cc 100644
--- a/webkit/integration-tests/testapp/src/main/java/com/example/androidx/webkit/SafeBrowsingActivity.java
+++ b/webkit/integration-tests/testapp/src/main/java/com/example/androidx/webkit/SafeBrowsingActivity.java

@@ -78,6 +78,9 @@
                 new MenuListView.MenuItem(
                         getResources().getString(R.string.loud_interstitial_activity_title),
                         new Intent(activityContext, LoudInterstitialActivity.class)),
+                new MenuListView.MenuItem(
+                        getResources().getString(R.string.giant_interstitial_activity_title),
+                        new Intent(activityContext, GiantInterstitialActivity.class)),
         };
         listView.setItems(menuItems);
     }