Add support for highlighting menu items

chrome/android/java/src/org/chromium/chrome/browser/appmenu/AppMenuHandler.java

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.appmenu;
 
 import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.content.res.TypedArray;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
+import android.support.annotation.IdRes;
 import android.view.ContextThemeWrapper;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.widget.PopupMenu;
 
 import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
 
 import java.util.ArrayList;
 
 /**
  * Object responsible for handling the creation, showing, hiding of the AppMenu and notifying the
  * AppMenuObservers about these actions.
  */
 public class AppMenuHandler {
     private AppMenu mAppMenu;
     private AppMenuDragHelper mAppMenuDragHelper;
     private Menu mMenu;
     private final ArrayList<AppMenuObserver> mObservers;
     private final int mMenuResourceId;
     private final View mHardwareButtonMenuAnchor;
 
     private final AppMenuPropertiesDelegate mDelegate;
     private final Activity mActivity;
 
     /**
+     * The resource id of the menu item to highlight when the menu next opens. A value of 0 means
+     * no item will be highlighted.  This value will be cleared after the menu is opened.
+     */
+    @IdRes
+    private int mHighlightMenuId;
+
+    /**
      * Constructs an AppMenuHandler object.
      * @param activity Activity that is using the AppMenu.
      * @param delegate Delegate used to check the desired AppMenu properties on show.
      * @param menuResourceId Resource Id that should be used as the source for the menu items.
      *            It is assumed to have back_menu_id, forward_menu_id, bookmark_this_page_id.
      */
     public AppMenuHandler(Activity activity, AppMenuPropertiesDelegate delegate,
             int menuResourceId) {
         mActivity = activity;
         mDelegate = delegate;
         mObservers = new ArrayList<AppMenuObserver>();
         mMenuResourceId = menuResourceId;
         mHardwareButtonMenuAnchor = activity.findViewById(R.id.menu_anchor_stub);
         assert mHardwareButtonMenuAnchor != null
                 : "Using AppMenu requires to have menu_anchor_stub view";
     }
 
     /**
      * Notifies the menu that the contents of the menu item specified by {@code menuRowId} have
      * changed.  This should be called if icons, titles, etc. are changing for a particular menu
      * item while the menu is open.
      * @param menuRowId The id of the menu item to change.  This must be a row id and not a child
      *                  id.
      */
     public void menuItemContentChanged(int menuRowId) {
         if (mAppMenu != null) mAppMenu.menuItemContentChanged(menuRowId);
     }
 
     /**
+     * Calls attention to this menu and a particular item in it.  The menu will only stay
+     * highlighted for one menu usage.  After that the highlight will be cleared.
+     * @param highlightItemId The id of a menu item to highlight or {@code 0} to turn off the
+     *                        highlight.
+     */
+    public void setMenuHighlight(@IdRes int highlightItemId) {
+        if (mHighlightMenuId == highlightItemId) return;
+        mHighlightMenuId = highlightItemId;
+        boolean highlighting = mHighlightMenuId != 0;
+        for (AppMenuObserver observer : mObservers) observer.onMenuHighlightChanged(highlighting);
+    }
+
+    /**
      * Show the app menu.
-     * @param anchorView         Anchor view (usually a menu button) to be used for the popup, if
-     *                           null is passed then hardware menu button anchor will be used.
-     * @param startDragging      Whether dragging is started. For example, if the app menu is
-     *                           showed by tapping on a button, this should be false. If it is
-     *                           showed by start dragging down on the menu button, this should
-     *                           be true. Note that if anchorView is null, this must
-     *                           be false since we no longer support hardware menu button
-     *                           dragging.
-     * @return True, if the menu is shown, false, if menu is not shown, example reasons:
-     *         the menu is not yet available to be shown, or the menu is already showing.
+     * @param anchorView    Anchor view (usually a menu button) to be used for the popup, if null is
+     *                      passed then hardware menu button anchor will be used.
+     * @param startDragging Whether dragging is started. For example, if the app menu is showed by
+     *                      tapping on a button, this should be false. If it is showed by start
+     *                      dragging down on the menu button, this should be true. Note that if
+     *                      anchorView is null, this must be false since we no longer support
+     *                      hardware menu button dragging.
+     * @return              True, if the menu is shown, false, if menu is not shown, example
+     *                      reasons: the menu is not yet available to be shown, or the menu is
+     *                      already showing.
      */
     // TODO(crbug.com/635567): Fix this properly.
     @SuppressLint("ResourceType")
     public boolean showAppMenu(View anchorView, boolean startDragging) {
         if (!mDelegate.shouldShowAppMenu() || isAppMenuShowing()) return false;
         boolean isByPermanentButton = false;
 
         int rotation = mActivity.getWindowManager().getDefaultDisplay().getRotation();
         if (anchorView == null) {
             // This fixes the bug where the bottom of the menu starts at the top of
@@ skipping 45 matching lines @@
             appRect.bottom = mActivity.getWindow().getDecorView().getHeight();
         }
         Point pt = new Point();
         mActivity.getWindowManager().getDefaultDisplay().getSize(pt);
 
         int footerResourceId = 0;
         if (mDelegate.shouldShowFooter(appRect.height())) {
             footerResourceId = mDelegate.getFooterResourceId();
         }
         mAppMenu.show(wrapper, anchorView, isByPermanentButton, rotation, appRect, pt.y,
-                footerResourceId);
+                footerResourceId, mHighlightMenuId);
         mAppMenuDragHelper.onShow(startDragging);
+        setMenuHighlight(0);
         RecordUserAction.record("MobileMenuShow");
         return true;
     }
 
     void appMenuDismissed() {
         mAppMenuDragHelper.finishDragging();
     }
 
     /**
      * @return Whether the App Menu is currently showing.
@@ skipping 43 matching lines @@
     /**
      * Called by AppMenu to report that the App Menu visibility has changed.
      * @param isVisible Whether the App Menu is showing.
      */
     void onMenuVisibilityChanged(boolean isVisible) {
         for (int i = 0; i < mObservers.size(); ++i) {
             mObservers.get(i).onMenuVisibilityChanged(isVisible);
         }
     }
 }