Set app menu shows from bottom after creation

This is a speculative fix for the app menu appearing off-screen. The
idea is that in some cases the bottom toolbar is initialized before
the app menu handler is (thus the flag to show from the bottom is
never set). This patch sets the value in both places so the order
doesn't matter.

Bug: 894555
Change-Id: I1faac37492e187896fff519ea7f1bf737605c8ae
Reviewed-on: https://chromium-review.googlesource.com/c/1306493Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603655}

chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarManager.java

@@ -1290,6 +1290,7 @@ public class ToolbarManager implements ToolbarTabController, UrlFocusChangeListe
             }
         });
         mAppMenuButtonHelper = new AppMenuButtonHelper(menuHandler);
+        mAppMenuButtonHelper.setMenuShowsFromBottom(mBottomToolbarCoordinator != null);
         mAppMenuButtonHelper.setOnAppMenuShownListener(() -> {
             RecordUserAction.record("MobileToolbarShowMenu");
             mToolbar.onMenuShown();