Fix NPE in recordClientConnectionStatus.

BUG=766695

Change-Id: Id1ab14ac9bd32aec910b2de4dd5cf8119ecd8eb8
Reviewed-on: https://chromium-review.googlesource.com/673203Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Maria Khomenko <mariakhomenko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#502919}

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java

@@ -985,7 +985,8 @@ public class CustomTabActivity extends ChromeActivity {
     }
 
     private void recordClientConnectionStatus() {
-        String packageName = getActivityTab().getAppAssociatedWith();
+        String packageName =
+                (getActivityTab() == null) ? null : getActivityTab().getAppAssociatedWith();
         if (packageName == null) return; // No associated package
 
         boolean isConnected = packageName.equals(