Don't show app menu if DecorView isn't attached to the Window

Bug: 1105831
Change-Id: Ic433031ce79b7eb837bbc6599f5a098760006704
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2299470Reviewed-by: Patrick Noland <pnoland@chromium.org>
Commit-Queue: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789225}

chrome/browser/ui/android/appmenu/internal/java/src/org/chromium/chrome/browser/ui/appmenu/AppMenuHandlerImpl.java

@@ -335,6 +335,12 @@ class AppMenuHandlerImpl
     }
 
     boolean shouldShowAppMenu() {
+        // If the activity's decor view is not attached to window, we don't show the app menu
+        // because the window manager might have revoked the window token for this activity. See
+        // https://crbug.com/1105831.
+        if (!mDecorView.isAttachedToWindow()) {
+            return false;
+        }
         for (int i = 0; i < mBlockers.size(); i++) {
             if (!mBlockers.get(i).canShowAppMenu()) return false;
         }