Add ContextMenuCoordinator.

ios/chrome/browser/ui/context_menu/context_menu_coordinator.mm

+// 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.
+
+#import "ios/chrome/browser/ui/context_menu/context_menu_coordinator.h"
+
+#include "base/ios/weak_nsobject.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/strings/sys_string_conversions.h"
+#import "ios/web/public/web_state/context_menu_params.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/strings/grit/ui_strings.h"
+
+@interface ContextMenuCoordinator () {
+  // Underlying system alert.
+  base::scoped_nsobject<UIAlertController> _alertController;
+  // View controller which will be used to present the |_alertController|.
+  base::WeakNSObject<UIViewController> _presentingViewController;
+  // Parameters that define what is shown in the context menu.
+  web::ContextMenuParams _params;
+}
+// Redefined to readwrite.
+@property(nonatomic, readwrite, getter=isVisible) BOOL visible;
+// Lazy initializer to create the |_alert|.
+@property(nonatomic, readonly) UIAlertController* alertController;
+// Called when the alert is dismissed to perform cleanup.
+- (void)alertDismissed;
+@end
+
+@implementation ContextMenuCoordinator
+@synthesize visible = _visible;
+
+- (instancetype)initWithViewController:(UIViewController*)viewController
+                                params:(const web::ContextMenuParams&)params {
+  self = [super init];
+  if (self) {
+    _params = params;
+    _presentingViewController.reset(viewController);
+  }
+  return self;
+}
+
+#pragma mark - Object Lifecycle
+- (void)dealloc {
+  [self stop];
+  [super dealloc];
+}
+
+#pragma mark - Public Methods
+- (void)addItemWithTitle:(NSString*)title action:(ProceduralBlock)actionBlock {
+  base::WeakNSObject<ContextMenuCoordinator> weakSelf(self);
+  void (^actionHandler)(UIAlertAction*) = ^(UIAlertAction*) {
+    [weakSelf alertDismissed];
+    actionBlock();
+  };
+  [self.alertController
+      addAction:[UIAlertAction actionWithTitle:title
+                                         style:UIAlertActionStyleDefault
+                                       handler:actionHandler]];
+}
+
+- (void)start {
+  // Check that the view is still visible on screen, otherwise just return and
+  // don't show the context menu.
+  if (![_params.view window] &&
+      ![_params.view isKindOfClass:[UIWindow class]]) {
+    return;
+  }
+
+  [_presentingViewController presentViewController:self.alertController
+                                          animated:YES
+                                        completion:nil];
+  self.visible = YES;
+}
+
+- (void)stop {
+  [_alertController dismissViewControllerAnimated:NO completion:nil];
+  [self setVisible:NO];
+  _alertController.reset();
+}
+
+#pragma mark - Property Implementation
+- (UIAlertController*)alertController {
+  if (!_alertController) {
+    DCHECK([_params.view isDescendantOfView:[_presentingViewController view]]);
+    UIAlertController* alert = [UIAlertController
+        alertControllerWithTitle:_params.menu_title
+                         message:nil
+                  preferredStyle:UIAlertControllerStyleActionSheet];
+    alert.popoverPresentationController.sourceView = _params.view;
+    alert.popoverPresentationController.sourceRect =
+        CGRectMake(_params.location.x, _params.location.y, 1.0, 1.0);
+
+    base::WeakNSObject<ContextMenuCoordinator> weakSelf(self);
+    UIAlertAction* cancelAction =
+        [UIAlertAction actionWithTitle:l10n_util::GetNSString(IDS_APP_CANCEL)
+                                 style:UIAlertActionStyleCancel
+                               handler:^(UIAlertAction*) {
+                                 [weakSelf alertDismissed];
+                               }];
+    [alert addAction:cancelAction];
+
+    _alertController.reset([alert retain]);
+  }
+  return _alertController;
+}
+
+#pragma mark - Private Methods
+- (void)alertDismissed {
+  self.visible = NO;
+  _alertController.reset();
+}
+
+@end