[iOS] Set up stub transition animators for Tab Grid.

This CL sets up stub implementations for the Tabb Grid transition
animators and helper objects/protocols.

Bug: 804537
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ie030f3222a93774e9da6a90b02cd865350f2dd37
Reviewed-on: https://chromium-review.googlesource.com/924756
Commit-Queue: Mark Cogan <marq@chromium.org>
Reviewed-by: edchin <edchin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537537}

ios/chrome/browser/ui/tab_grid/BUILD.gn

@@ -39,6 +39,9 @@ source_set("tab_grid_ui") {
     "tab_grid_bottom_toolbar.mm",
     "tab_grid_top_toolbar.h",
     "tab_grid_top_toolbar.mm",
+    "tab_grid_transition_handler.h",
+    "tab_grid_transition_handler.mm",
+    "tab_grid_transition_state_provider.h",
     "tab_grid_view_controller.h",
     "tab_grid_view_controller.mm",
   ]
@@ -47,6 +50,7 @@ source_set("tab_grid_ui") {
 
   deps = [
     "//base",
+    "//ios/chrome/browser/ui/tab_grid/transitions",
     "//ios/chrome/browser/ui/util:constraints_ui",
   ]
 }

ios/chrome/browser/ui/tab_grid/tab_grid_coordinator.mm

@@ -8,20 +8,23 @@
 #import "ios/chrome/browser/ui/main/bvc_container_view_controller.h"
 #import "ios/chrome/browser/ui/tab_grid/tab_grid_adaptor.h"
 #import "ios/chrome/browser/ui/tab_grid/tab_grid_mediator.h"
+#import "ios/chrome/browser/ui/tab_grid/tab_grid_transition_handler.h"
 #import "ios/chrome/browser/ui/tab_grid/tab_grid_view_controller.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
-@interface TabGridCoordinator ()<UIViewControllerTransitioningDelegate>
-// Object that internally backs the public TabSwitcher
+@interface TabGridCoordinator ()
+// Object that internally backs the public  TabSwitcher
 @property(nonatomic, strong) TabGridAdaptor* adaptor;
 // Container view controller for the BVC to live in; this class's view
 // controller will present this.
 @property(nonatomic, strong) BVCContainerViewController* bvcContainer;
 // Mediates between the model layer and the tab grid UI layer.
 @property(nonatomic, strong) TabGridMediator* mediator;
+// Transitioning delegate for the view controller.
+@property(nonatomic, strong) TabGridTransitionHandler* transitionHandler;
 @end
 
 @implementation TabGridCoordinator
@@ -35,6 +38,7 @@
 @synthesize adaptor = _adaptor;
 @synthesize bvcContainer = _bvcContainer;
 @synthesize mediator = _mediator;
+@synthesize transitionHandler = _transitionHandler;
 
 #pragma mark - Public properties
 
@@ -51,8 +55,11 @@
 #pragma mark - ChromeCoordinator
 
 - (void)start {
-  UIViewController* mainViewController = [[TabGridViewController alloc] init];
-  mainViewController.transitioningDelegate = self;
+  TabGridViewController* mainViewController =
+      [[TabGridViewController alloc] init];
+  self.transitionHandler = [[TabGridTransitionHandler alloc] init];
+  self.transitionHandler.provider = mainViewController;
+  mainViewController.transitioningDelegate = self.transitionHandler;
   _mainViewController = mainViewController;
   self.window.rootViewController = self.mainViewController;
   self.adaptor = [[TabGridAdaptor alloc] init];
@@ -63,22 +70,6 @@
   self.mediator.incognitoTabModel = self.incognitoTabModel;
 }
 
-#pragma mark - UIViewControllerTransitioningDelegate
-
-- (id<UIViewControllerAnimatedTransitioning>)
-animationControllerForPresentedController:(UIViewController*)presented
-                     presentingController:(UIViewController*)presenting
-                         sourceController:(UIViewController*)source {
-  return nil;
-}
-
-- (id<UIViewControllerAnimatedTransitioning>)
-animationControllerForDismissedController:(UIViewController*)dismissed {
-  // Verify that the presenting and dismissed view controllers are of the
-  // expected types.
-  return nil;
-}
-
 #pragma mark - ViewControllerSwapping
 
 - (UIViewController*)activeViewController {
@@ -105,7 +96,7 @@ animationControllerForDismissedController:(UIViewController*)dismissed {
   // If a BVC is currently being presented, dismiss it.  This will trigger any
   // necessary animations.
   if (self.bvcContainer) {
-    self.bvcContainer.transitioningDelegate = self;
+    self.bvcContainer.transitioningDelegate = self.transitionHandler;
     self.bvcContainer = nil;
     BOOL animated = !self.animationsDisabledForTesting;
     [self.mainViewController dismissViewControllerAnimated:animated
@@ -133,7 +124,7 @@ animationControllerForDismissedController:(UIViewController*)dismissed {
 
   self.bvcContainer = [[BVCContainerViewController alloc] init];
   self.bvcContainer.currentBVC = viewController;
-  self.bvcContainer.transitioningDelegate = self;
+  self.bvcContainer.transitioningDelegate = self.transitionHandler;
   BOOL animated = !self.animationsDisabledForTesting;
   [self.mainViewController presentViewController:self.bvcContainer
                                         animated:animated

ios/chrome/browser/ui/tab_grid/tab_grid_transition_handler.h

+// Copyright 2018 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_TAB_GRID_TAB_GRID_TRANSITION_HANDLER_H_
+#define IOS_CHROME_BROWSER_UI_TAB_GRID_TAB_GRID_TRANSITION_HANDLER_H_
+
+#import <UIKit/UIKit.h>
+
+@protocol TabGridTransitionStateProvider;
+
+@interface TabGridTransitionHandler
+    : NSObject<UIViewControllerTransitioningDelegate>
+
+@property(nonatomic, weak) id<TabGridTransitionStateProvider> provider;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TAB_GRID_TAB_GRID_TRANSITION_HANDLER_H_

ios/chrome/browser/ui/tab_grid/tab_grid_transition_handler.mm

+// Copyright 2018 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/tab_grid/tab_grid_transition_handler.h"
+
+#import "ios/chrome/browser/ui/tab_grid/tab_grid_transition_state_provider.h"
+#import "ios/chrome/browser/ui/tab_grid/transitions/grid_to_hidden_tab_animator.h"
+#import "ios/chrome/browser/ui/tab_grid/transitions/grid_to_visible_tab_animator.h"
+#import "ios/chrome/browser/ui/tab_grid/transitions/tab_to_grid_animator.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@implementation TabGridTransitionHandler
+
+@synthesize provider = _provider;
+
+#pragma mark - UIViewControllerTransitioningDelegate
+
+- (id<UIViewControllerAnimatedTransitioning>)
+animationControllerForPresentedController:(UIViewController*)presented
+                     presentingController:(UIViewController*)presenting
+                         sourceController:(UIViewController*)source {
+  id<UIViewControllerAnimatedTransitioning> animator;
+  if (self.provider.selectedTabVisible) {
+    // This will be a GridToVisibleTabAnimator eventually.
+    animator = nil;
+  } else {
+    // This will be a GridToHiddenTabAnimator eventually.
+    animator = nil;
+  }
+  return animator;
+}
+
+- (id<UIViewControllerAnimatedTransitioning>)
+animationControllerForDismissedController:(UIViewController*)dismissed {
+  // This will be a TabToGridAnimator eventually.
+  return nil;
+}
+
+@end

ios/chrome/browser/ui/tab_grid/tab_grid_transition_state_provider.h

+// Copyright 2018 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_TAB_GRID_TAB_GRID_TRANSITION_STATE_PROVIDER_H_
+#define IOS_CHROME_BROWSER_UI_TAB_GRID_TAB_GRID_TRANSITION_STATE_PROVIDER_H_
+
+#import <Foundation/Foundation.h>
+
+// Objects conforming to this protocol can provide state information to
+// transition delegates and animators for the tab grid.
+@protocol TabGridTransitionStateProvider
+
+// YES if the currently selected tab is visible in the tab grid.
+@property(nonatomic, readonly) BOOL selectedTabVisible;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TAB_GRID_TAB_GRID_TRANSITION_STATE_PROVIDER_H_

ios/chrome/browser/ui/tab_grid/tab_grid_view_controller.h

@@ -8,12 +8,16 @@
 #import <UIKit/UIKit.h>
 
 #import "ios/chrome/browser/ui/tab_grid/grid_consumer.h"
+#import "ios/chrome/browser/ui/tab_grid/tab_grid_transition_state_provider.h"
 
-// View controller representing a tab switcher. The tab switcher has an
+// View controller representing a tab switcher.  The tab switcher has an
 // incognito tab grid, regular tab grid, and remote tabs.
-@interface TabGridViewController : UIViewController
+@interface TabGridViewController
+    : UIViewController<TabGridTransitionStateProvider>
+
 @property(nonatomic, readonly) id<GridConsumer> regularTabsConsumer;
 @property(nonatomic, readonly) id<GridConsumer> incognitoTabsConsumer;
+
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_TAB_GRID_TAB_GRID_VIEW_CONTROLLER_H_

ios/chrome/browser/ui/tab_grid/tab_grid_view_controller.mm

@@ -93,7 +93,7 @@
                            constraintEqualToAnchor:self.view.trailingAnchor],
                        nil];
   if (@available(iOS 11, *)) {
-    // SafeArea is only available in iOS 11+.
+    // SafeArea is only available in iOS  11+.
     [constraints addObjectsFromArray:@[
       [topToolbar.bottomAnchor
           constraintEqualToAnchor:self.view.safeAreaLayoutGuide.topAnchor
@@ -122,4 +122,10 @@
                        bottomToolbar.intrinsicContentSize.height, 0);
 }
 
+#pragma mark - TabGridTransitionStateProvider properties
+
+- (BOOL)selectedTabVisible {
+  return NO;
+}
+
 @end

ios/chrome/browser/ui/tab_grid/transitions/BUILD.gn

+# Copyright 2018 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/public/provider/chrome/browser/build_config.gni")
+
+source_set("transitions") {
+  sources = [
+    "grid_to_hidden_tab_animator.h",
+    "grid_to_hidden_tab_animator.mm",
+    "grid_to_visible_tab_animator.h",
+    "grid_to_visible_tab_animator.mm",
+    "tab_to_grid_animator.h",
+    "tab_to_grid_animator.mm",
+  ]
+
+  configs += [ "//build/config/compiler:enable_arc" ]
+
+  deps = [
+    "//base",
+  ]
+}

ios/chrome/browser/ui/tab_grid/transitions/grid_to_hidden_tab_animator.h

+// Copyright 2018 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_TAB_GRID_TRANSITIONS_GRID_TO_HIDDEN_TAB_ANIMATOR_H_
+#define IOS_CHROME_BROWSER_UI_TAB_GRID_TRANSITIONS_GRID_TO_HIDDEN_TAB_ANIMATOR_H_
+
+#import <UIKit/UIKit.h>
+
+@interface GridToHiddenTabAnimator
+    : NSObject<UIViewControllerAnimatedTransitioning>
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TAB_GRID_TRANSITIONS_GRID_TO_HIDDEN_TAB_ANIMATOR_H_

ios/chrome/browser/ui/tab_grid/transitions/grid_to_hidden_tab_animator.mm

+// Copyright 2018 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/tab_grid/transitions/grid_to_hidden_tab_animator.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@implementation GridToHiddenTabAnimator
+
+- (NSTimeInterval)transitionDuration:
+    (id<UIViewControllerContextTransitioning>)transitionContext {
+  return 0.25;
+}
+
+- (void)animateTransition:
+    (id<UIViewControllerContextTransitioning>)transitionContext {
+}
+
+@end

ios/chrome/browser/ui/tab_grid/transitions/grid_to_visible_tab_animator.h

+// Copyright 2018 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_TAB_GRID_TRANSITIONS_GRID_TO_VISIBLE_TAB_ANIMATOR_H_
+#define IOS_CHROME_BROWSER_UI_TAB_GRID_TRANSITIONS_GRID_TO_VISIBLE_TAB_ANIMATOR_H_
+
+#import <UIKit/UIKit.h>
+
+@interface GridToVisibleTabAnimator
+    : NSObject<UIViewControllerAnimatedTransitioning>
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TAB_GRID_TRANSITIONS_GRID_TO_VISIBLE_TAB_ANIMATOR_H_

ios/chrome/browser/ui/tab_grid/transitions/grid_to_visible_tab_animator.mm

+// Copyright 2018 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/tab_grid/transitions/grid_to_visible_tab_animator.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@implementation GridToVisibleTabAnimator
+
+- (NSTimeInterval)transitionDuration:
+    (id<UIViewControllerContextTransitioning>)transitionContext {
+  return 0.25;
+}
+
+- (void)animateTransition:
+    (id<UIViewControllerContextTransitioning>)transitionContext {
+}
+
+@end

ios/chrome/browser/ui/tab_grid/transitions/tab_to_grid_animator.h

+// Copyright 2018 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_TAB_GRID_TRANSITIONS_TAB_TO_GRID_ANIMATOR_H_
+#define IOS_CHROME_BROWSER_UI_TAB_GRID_TRANSITIONS_TAB_TO_GRID_ANIMATOR_H_
+
+#import <UIKit/UIKit.h>
+
+@interface TabToGridAnimator : NSObject<UIViewControllerAnimatedTransitioning>
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TAB_GRID_TRANSITIONS_TAB_TO_GRID_ANIMATOR_H_

ios/chrome/browser/ui/tab_grid/transitions/tab_to_grid_animator.mm

+// Copyright 2018 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/tab_grid/transitions/tab_to_grid_animator.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@implementation TabToGridAnimator
+
+- (NSTimeInterval)transitionDuration:
+    (id<UIViewControllerContextTransitioning>)transitionContext {
+  return 0.25;
+}
+
+- (void)animateTransition:
+    (id<UIViewControllerContextTransitioning>)transitionContext {
+}
+
+@end