Upstream Chrome on iOS source code [8/11].

ios/chrome/browser/ui/tab/tab_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.
+
+// ======                        New Architecture                         =====
+// =         This code is only used in the new iOS Chrome architecture.       =
+// ============================================================================
+
+#import "ios/chrome/browser/ui/tab/tab_coordinator.h"
+
+#include <memory>
+
+#include "base/mac/foundation_util.h"
+#include "base/memory/ptr_util.h"
+#import "ios/chrome/browser/browser_coordinator+internal.h"
+#import "ios/chrome/browser/ui/animators/zoom_transition_animator.h"
+#import "ios/chrome/browser/ui/tab/tab_container_view_controller.h"
+#import "ios/chrome/browser/ui/toolbar/toolbar_coordinator.h"
+#import "ios/chrome/browser/ui/web_contents/web_coordinator.h"
+#import "ios/web/public/web_state/web_state_observer_bridge.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace {
+// Placeholder "experiment" flag. Change this to YES to have the toolbar at the
+// bottom.
+const BOOL kUseBottomToolbar = NO;
+}  // namespace
+
+@interface TabCoordinator ()<UIViewControllerTransitioningDelegate>
+@property(nonatomic, strong) TabContainerViewController* viewController;
+@end
+
+@implementation TabCoordinator {
+  std::unique_ptr<web::WebStateObserverBridge> _webStateObserver;
+}
+
+@synthesize webState = _webState;
+@synthesize presentationKey = _presentationKey;
+@synthesize viewController = _viewController;
+
+- (void)start {
+  self.viewController = [self newTabContainer];
+  self.viewController.transitioningDelegate = self;
+  self.viewController.modalPresentationStyle = UIModalPresentationCustom;
+
+  WebCoordinator* webCoordinator = [[WebCoordinator alloc] init];
+  webCoordinator.webState = self.webState;
+  [self addChildCoordinator:webCoordinator];
+  // Unset the root view controller, so |webCoordinator| doesn't present its
+  // view controller.
+  webCoordinator.rootViewController = nil;
+  [webCoordinator start];
+
+  ToolbarCoordinator* toolbarCoordinator = [[ToolbarCoordinator alloc] init];
+  [self addChildCoordinator:toolbarCoordinator];
+  // TODO: Instead of this, let WebMediator maintain a set of webStateObservers
+  // and just provide -addObserver and -stopObserving methods.
+  _webStateObserver = base::MakeUnique<web::WebStateObserverBridge>(
+      self.webState, toolbarCoordinator);
+  // Unset the .base view controller, so |toolbarCoordinator| doesn't present
+  // its view controller.
+  toolbarCoordinator.rootViewController = nil;
+  [toolbarCoordinator start];
+
+  self.viewController.toolbarViewController = toolbarCoordinator.viewController;
+  self.viewController.contentViewController = webCoordinator.viewController;
+
+  [self.rootViewController presentViewController:self.viewController
+                                        animated:YES
+                                      completion:nil];
+}
+
+- (void)stop {
+  [self.viewController dismissViewControllerAnimated:YES completion:nil];
+  _webStateObserver.reset();
+}
+
+- (BOOL)canAddOverlayCoordinator:(BrowserCoordinator*)overlayCoordinator {
+  // This coordinator will always accept overlay coordinators.
+  return YES;
+}
+
+#pragma mark - Experiment support
+
+// Create and return a new view controller for use as a tab container;
+// experimental configurations determine which subclass of
+// TabContainerViewController to return.
+- (TabContainerViewController*)newTabContainer {
+  if (kUseBottomToolbar) {
+    return [[BottomToolbarTabViewController alloc] init];
+  }
+  return [[TopToolbarTabViewController alloc] init];
+}
+
+#pragma mark - UIViewControllerTransitioningDelegate
+
+- (id<UIViewControllerAnimatedTransitioning>)
+animationControllerForPresentedController:(UIViewController*)presented
+                     presentingController:(UIViewController*)presenting
+                         sourceController:(UIViewController*)source {
+  ZoomTransitionAnimator* animator = [[ZoomTransitionAnimator alloc] init];
+  animator.presenting = YES;
+  animator.presentationKey = self.presentationKey;
+  [animator selectDelegate:@[ source, presenting ]];
+  return animator;
+}
+
+- (id<UIViewControllerAnimatedTransitioning>)
+animationControllerForDismissedController:(UIViewController*)dismissed {
+  ZoomTransitionAnimator* animator = [[ZoomTransitionAnimator alloc] init];
+  animator.presenting = NO;
+  animator.presentationKey = self.presentationKey;
+  [animator selectDelegate:@[ dismissed.presentingViewController ]];
+  return animator;
+}
+
+@end