[iOS Clean] Wired up ContextMenuCommands.

ios/clean/chrome/browser/ui/context_menu/web_context_menu_coordinator.mm

 // Copyright 2017 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.
 
 #import "ios/clean/chrome/browser/ui/context_menu/web_context_menu_coordinator.h"
 
+#include "base/logging.h"
+#import "ios/clean/chrome/browser/ui/commands/context_menu_commands.h"
+#import "ios/clean/chrome/browser/ui/context_menu/context_menu_context_impl.h"
 #import "ios/clean/chrome/browser/ui/context_menu/context_menu_mediator.h"
 #import "ios/clean/chrome/browser/ui/context_menu/context_menu_view_controller.h"
 #import "ios/shared/chrome/browser/ui/browser_list/browser.h"
 #import "ios/shared/chrome/browser/ui/commands/command_dispatcher.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
-@interface WebContextMenuCoordinator ()
+@interface WebContextMenuCoordinator ()<ContextMenuCommands>
+// The menu context.
+@property(nonatomic, strong, readonly) ContextMenuContextImpl* context;
+// The mediator that handles setting up |viewController|.
 @property(nonatomic, strong) ContextMenuMediator* mediator;
+// The view controller that displayes the context menu UI.
 @property(nonatomic, strong) ContextMenuViewController* viewController;
+
 @end
 
 @implementation WebContextMenuCoordinator
+@synthesize context = _context;
+@synthesize mediator = _mediator;
 @synthesize viewController = _viewController;
-@synthesize mediator = _mediator;
+
+- (instancetype)initWithContext:(ContextMenuContextImpl*)context {
+  if ((self = [super init])) {
+    DCHECK(context);
+    _context = context;
+  }
+  return self;
+}
+
+#pragma mark - BrowserCoordinator
 
 - (void)start {
+  id<ContextMenuCommands> contextMenuDispatcher =
+      static_cast<id<ContextMenuCommands>>(self.browser->dispatcher());
   self.viewController = [[ContextMenuViewController alloc]
-      initWithDispatcher:static_cast<id>(self.browser->dispatcher())];
+      initWithDispatcher:contextMenuDispatcher];
   self.mediator =

[edchin, 2017/05/25 21:41:53]

Since the mediator does its job in its initializer, 
there's no need to keep it around as a property. 
Can we remove the property?

[kkhorimoto, 2017/05/26 23:20:09]

Doing that gave me an unused variable warning when I tried to compile.  Since
there's no real reason to instantiate an object here, I've converted the
mediator's initializer to a class function that performs the work of setting the
items.  For consumers like the context menu that only require a 1-time
configuration, do we still want to try to use the mediator pattern like I'm
doing here, or should we just fold setup into a utility function or something?

[edchin, 2017/05/27 15:59:03]

Interesting question. This is the only mediator that I know of that doesn't have
some asynchronous observer. Given that it's unique, 
I suggest we leave this as you have it, and see if this pattern emerges more
commonly. 

[kkhorimoto, 2017/05/27 23:09:03]

I'm also working on the javascript dialog coordinator, and they also require
only a one-time setup.  This will be true for any UI that doesn't update after
being presented.  For now, I've followed the same pattern as here, using a class
method to setup the consumer.

-      [[ContextMenuMediator alloc] initWithConsumer:self.viewController];
+      [[ContextMenuMediator alloc] initWithConsumer:self.viewController
+                                            context:self.context];
+  [self.browser->dispatcher()
+      startDispatchingToTarget:self
+                   forSelector:@selector(hideContextMenu:)];
   [super start];
 }
 
+- (void)stop {
+  [self.browser->dispatcher() stopDispatchingToTarget:self];
+  [super stop];
+}
+
+#pragma mark - ContextMenuCommands
+
+- (void)hideContextMenu:(ContextMenuContext*)context {
+  DCHECK_EQ(self.context, context);
+  [self stop];
+}
+
 @end