Add ContextMenuCoordinator.

ios/chrome/browser/ui/context_menu/context_menu_wrangler.h

+// Copyright 2016 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.
+
+#ifndef IOS_CHROME_BROWSER_UI_CONTEXT_MENU_CONTEXT_MENU_WRANGLER_H_
+#define IOS_CHROME_BROWSER_UI_CONTEXT_MENU_CONTEXT_MENU_WRANGLER_H_
+
+#import <UIKit/UIKit.h>
+
+#include "base/ios/block_types.h"
+
+namespace web {
+struct ContextMenuParams;
+}
+
+// Abstracts displaying context menus for all device form factors. Will show a
+// sheet on the phone and use a popover on a tablet.
+@interface ContextMenuWrangler : NSObject
+
+// Whether the context menu is visible.
+@property(nonatomic, readonly, getter=isVisible) BOOL visible;

[Eugene But (OOO till 7-30), 2016/05/13 01:23:55]

Is this method actually needed? 

[michaeldo, 2016/05/17 18:03:03]

It is needed (for now). It is used downstream, I can PM you more details.

+
+// Initializes with details provided in |params|.
+- (instancetype)initWithContextMenuParams:(const web::ContextMenuParams&)params;

[marq (ping after 24h), 2016/05/13 14:51:29]

I'd like coordinators to typically accept a view controller as a parameter; in
this case it would be used as the VC that the context menu is presented from.

[michaeldo, 2016/05/17 18:03:03]

Done.

+// Adds an item at the end of the menu.
+- (void)addItemWithTitle:(NSString*)title action:(ProceduralBlock)action;
+// Displays the context menu.
+- (void)present;

[marq (ping after 24h), 2016/05/13 14:51:29]

The coordinator's job is to manage a discrete UI interaction; I prefer 'start'
as the verb/method name used to kick things off.

[michaeldo, 2016/05/17 18:03:03]

Done.

+
+// Dismisses displayed context menu.
+- (void)dismissAnimated:(BOOL)animated

[marq (ping after 24h), 2016/05/13 14:51:29]

What's the use case for this being called by external code? My preference would
be for a 'stop' method that determines if any animation needs to happen
internally.

[michaeldo, 2016/05/17 18:03:03]

This appears to only be called from "dismissModals", so it would be no
animation. I have updated it.

+      completionHandler:(ProceduralBlock)completionHandler;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_CONTEXT_MENU_CONTEXT_MENU_WRANGLER_H_