Simple strip container that can reveal/hide tab strip.

The simple strip container is WIP and this CL has only
minimal functionality. This CL also showcases this
strip container in Showcase.

BUG=none.

Review-Url: https://codereview.chromium.org/2594023002
Cr-Commit-Position: refs/heads/master@{#440853}

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

@@ -6,6 +6,7 @@ source_set("actions") {
   sources = [
     "settings_actions.h",
     "tab_grid_actions.h",
+    "tab_strip_actions.h",
     "tools_menu_actions.h",
   ]
 

ios/chrome/browser/ui/actions/tab_strip_actions.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.
+
+// ======                        New Architecture                         =====
+// =         This code is only used in the new iOS Chrome architecture.       =
+// ============================================================================
+
+#ifndef IOS_CHROME_BROWSER_UI_ACTIONS_TAB_STRIP_ACTIONS_H_
+#define IOS_CHROME_BROWSER_UI_ACTIONS_TAB_STRIP_ACTIONS_H_
+
+#import <Foundation/Foundation.h>
+
+// Target/Action methods relating to the tab strip.
+@protocol TabStripActions
+@optional
+// Reveals or hides the tab strip.
+- (void)toggleTabStrip:(id)sender;
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_ACTIONS_TAB_STRIP_ACTIONS_H_

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

+# 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.
+
+source_set("strip_ui") {
+  sources = [
+    "strip_container_view_controller.h",
+    "strip_container_view_controller.mm",
+  ]
+  deps = [
+    "//ios/chrome/browser/ui:ui_clean_skeleton",
+    "//ios/chrome/browser/ui/actions",
+  ]
+  libs = [ "UIKit.framework" ]
+  configs += [ "//build/config/compiler:enable_arc" ]
+}

ios/chrome/browser/ui/strip/strip_container_view_controller.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.
+
+// ======                        New Architecture                         =====
+// =         This code is only used in the new iOS Chrome architecture.       =
+// ============================================================================
+
+#ifndef IOS_CHROME_BROWSER_UI_STRIP_STRIP_CONTAINER_VIEW_CONTROLLER_H_
+#define IOS_CHROME_BROWSER_UI_STRIP_STRIP_CONTAINER_VIEW_CONTROLLER_H_
+
+#import <UIKit/UIKit.h>
+
+// Base class for a view controller that contains a content view (generally a
+// web view with toolbar, but nothing in this class assumes that) and a strip
+// view, each managed by their own view controllers.
+@interface StripContainerViewController : UIViewController
+
+// View controller showing the main content. If there is no strip view
+// controller set, the contents of this view controller will fill all of the
+// strip container's view.
+@property(nonatomic, strong) UIViewController* contentViewController;
+
+// View controller showing the strip. It will be of a fixed
+// height (determined internally by the strip container), but will span the
+// width of the tab.
+@property(nonatomic, strong) UIViewController* stripViewController;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_STRIP_STRIP_CONTAINER_VIEW_CONTROLLER_H_

ios/chrome/browser/ui/strip/strip_container_view_controller.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/strip/strip_container_view_controller.h"
+
+#import "ios/chrome/browser/ui/ui_types.h"
+#import "ios/chrome/browser/ui/actions/tab_strip_actions.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace {
+CGFloat kStripHeight = 200.0;
+}
+
+@interface StripContainerViewController ()<TabStripActions>
+
+// Whichever view controller is at the top of the screen. This view controller
+// controls the status bar.
+@property(nonatomic, weak) UIViewController* topmostViewController;
+
+@property(nonatomic, strong) Constraints* contentConstraintsWithStrip;
+@property(nonatomic, strong) Constraints* contentConstraintsWithoutStrip;
+@property(nonatomic, strong) Constraints* stripConstraints;
+
+// Cache for forwarding methods to child view controllers.
+@property(nonatomic, assign) SEL actionToForward;
+@property(nonatomic, weak) UIResponder* forwardingTarget;
+
+@property(nonatomic, strong) NSLayoutConstraint* stripHeightConstraint;
+
+// Contained view controller utility methods.
+- (void)removeChildViewController:(UIViewController*)viewController;
+
+// Called after a new content view controller is set, but before
+// |-didMoveToParentViewController:| is called on that view controller.
+- (void)didAddContentViewController;
+
+// Called after a new strip view controller is set, but before
+// |-didMoveToParentViewController:| is called on that view controller.
+- (void)didAddStripViewController;
+
+// Methods to populate the constraint properties.
+- (void)updateContentConstraintsWithStrip;
+- (void)updateContentConstraintsWithoutStrip;
+- (void)updateStripConstraints;
+
+@end
+
+@implementation StripContainerViewController
+
+@synthesize contentViewController = _contentViewController;
+@synthesize stripViewController = _stripViewController;
+@synthesize topmostViewController = _topmostViewController;
+@synthesize contentConstraintsWithStrip = _contentConstraintsWithStrip;
+@synthesize contentConstraintsWithoutStrip = _contentConstraintsWithoutStrip;
+@synthesize stripConstraints = _stripConstraints;
+@synthesize actionToForward = _actionToForward;
+@synthesize forwardingTarget = _forwardingTarget;
+@synthesize stripHeightConstraint = _stripHeightConstraint;
+
+#pragma mark - Public properties
+
+- (void)setContentViewController:(UIViewController*)contentViewController {
+  if (self.contentViewController == contentViewController)
+    return;
+
+  // Remove the current content view controller, if any.
+  [NSLayoutConstraint
+      deactivateConstraints:self.contentConstraintsWithoutStrip];
+  [NSLayoutConstraint deactivateConstraints:self.contentConstraintsWithStrip];
+  [self removeChildViewController:self.contentViewController];
+
+  // Add the new content view controller.
+  [self addChildViewController:contentViewController];
+  contentViewController.view.translatesAutoresizingMaskIntoConstraints = NO;
+  [self.view addSubview:contentViewController.view];
+  _contentViewController = contentViewController;
+  [self didAddContentViewController];
+  [self.view setNeedsUpdateConstraints];
+  [self.contentViewController didMoveToParentViewController:self];
+}
+
+- (void)setStripViewController:(UIViewController*)stripViewController {
+  if (self.stripViewController == stripViewController)
+    return;
+
+  // Remove the current strip view controller, if any.
+  [NSLayoutConstraint deactivateConstraints:self.stripConstraints];
+  [NSLayoutConstraint deactivateConstraints:self.contentConstraintsWithStrip];
+  [self removeChildViewController:self.stripViewController];
+
+  // Add the new strip view controller.
+  [self addChildViewController:stripViewController];
+  stripViewController.view.translatesAutoresizingMaskIntoConstraints = NO;
+  [self.view addSubview:stripViewController.view];
+  _stripViewController = stripViewController;
+  [self didAddStripViewController];
+  [self.view setNeedsUpdateConstraints];
+  [self.stripViewController didMoveToParentViewController:self];
+}
+
+#pragma mark - UIViewController
+
+- (void)updateViewConstraints {
+  if (self.stripViewController) {
+    [NSLayoutConstraint activateConstraints:self.stripConstraints];
+    [NSLayoutConstraint activateConstraints:self.contentConstraintsWithStrip];
+  } else {
+    [NSLayoutConstraint
+        activateConstraints:self.contentConstraintsWithoutStrip];
+  }
+  [super updateViewConstraints];
+}
+
+- (UIViewController*)childViewControllerForStatusBarHidden {
+  return self.topmostViewController;
+}
+
+- (UIViewController*)childViewControllerForStatusBarStyle {
+  return self.topmostViewController;
+}
+
+#pragma mark - UIResponder
+
+// Before forwarding actions up the responder chain, give both contained
+// view controllers a chance to handle them.
+- (BOOL)canPerformAction:(SEL)action withSender:(id)sender {
+  self.actionToForward = nullptr;
+  self.forwardingTarget = nil;
+  for (UIResponder* responder in
+       @[ self.contentViewController, self.stripViewController ]) {
+    if ([responder canPerformAction:action withSender:sender]) {
+      self.actionToForward = action;
+      self.forwardingTarget = responder;
+      return YES;
+    }
+  }
+  return [super canPerformAction:action withSender:sender];
+}
+
+#pragma mark - NSObject method forwarding
+
+- (id)forwardingTargetForSelector:(SEL)aSelector {
+  if (aSelector == self.actionToForward) {
+    return self.forwardingTarget;
+  }
+  return nil;
+}
+
+#pragma mark - TabStripActions
+
+// Action to toggle visibility of tab strip.
+- (void)toggleTabStrip:(id)sender {
+  self.stripHeightConstraint.constant =
+      self.stripHeightConstraint.constant > 0 ? 0.0 : kStripHeight;
+}
+
+#pragma mark - Private methods
+
+- (void)removeChildViewController:(UIViewController*)viewController {
+  if (viewController.parentViewController != self)
+    return;
+  [viewController willMoveToParentViewController:nil];
+  [viewController.view removeFromSuperview];
+  [viewController removeFromParentViewController];
+}
+
+- (void)didAddContentViewController {
+  if (self.stripViewController) {
+    [self updateContentConstraintsWithStrip];
+  } else {
+    self.topmostViewController = self.contentViewController;
+    [self updateContentConstraintsWithoutStrip];
+  }
+}
+
+- (void)didAddStripViewController {
+  [self updateStripConstraints];
+  // If there's already a content view controller, update the constraints for
+  // that, too.
+  if (self.contentViewController) {
+    [self updateContentConstraintsWithStrip];
+  }
+  self.topmostViewController = self.stripViewController;
+}
+
+- (void)updateContentConstraintsWithoutStrip {
+  UIView* contentView = self.contentViewController.view;
+  self.contentConstraintsWithoutStrip = @[
+    [contentView.topAnchor constraintEqualToAnchor:self.view.topAnchor],
+    [contentView.bottomAnchor constraintEqualToAnchor:self.view.bottomAnchor],
+    [contentView.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor],
+    [contentView.trailingAnchor
+        constraintEqualToAnchor:self.view.trailingAnchor],
+  ];
+}
+
+- (void)updateContentConstraintsWithStrip {
+  UIView* contentView = self.contentViewController.view;
+  self.contentConstraintsWithStrip = @[
+    [contentView.topAnchor
+        constraintEqualToAnchor:self.stripViewController.view.bottomAnchor],
+    [contentView.bottomAnchor constraintEqualToAnchor:self.view.bottomAnchor],
+    [contentView.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor],
+    [contentView.trailingAnchor
+        constraintEqualToAnchor:self.view.trailingAnchor],
+  ];
+}
+
+- (void)updateStripConstraints {
+  UIView* stripView = self.stripViewController.view;
+  self.stripHeightConstraint =
+      [stripView.heightAnchor constraintEqualToConstant:0.0];
+  self.stripConstraints = @[
+    [stripView.topAnchor constraintEqualToAnchor:self.view.topAnchor],
+    [stripView.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor],
+    [stripView.trailingAnchor constraintEqualToAnchor:self.view.trailingAnchor],
+    self.stripHeightConstraint,
+  ];
+}
+
+@end

ios/showcase/BUILD.gn

@@ -27,6 +27,7 @@ group("features") {
   deps = [
     "//ios/chrome/browser/ui/tools:tools_ui",
     "//ios/showcase/settings",
+    "//ios/showcase/strip",
     "//ios/showcase/tab_grid",
     "//ios/showcase/uikit_table_view_cell",
   ]

ios/showcase/core/showcase_model.mm

@@ -36,6 +36,11 @@
       showcase::kClassForInstantiationKey : @"SCTabGridCoordinator",
       showcase::kUseCaseKey : @"Tab grid",
     },
+    @{
+      showcase::kClassForDisplayKey : @"StripContainerViewController",
+      showcase::kClassForInstantiationKey : @"SCStripCoordinator",
+      showcase::kUseCaseKey : @"Tab strip container",
+    },
   ];
 }
 

ios/showcase/strip/BUILD.gn

+# 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.
+
+source_set("strip") {
+  sources = [
+    "sc_strip_coordinator.h",
+    "sc_strip_coordinator.mm",
+  ]
+  deps = [
+    "//ios/chrome/browser/ui/actions",
+    "//ios/chrome/browser/ui/strip:strip_ui",
+    "//ios/showcase/common",
+  ]
+  libs = [ "UIKit.framework" ]
+  configs += [ "//build/config/compiler:enable_arc" ]
+}

ios/showcase/strip/sc_strip_coordinator.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_SHOWCASE_STRIP_SC_STRIP_COORDINATOR_H_
+#define IOS_SHOWCASE_STRIP_SC_STRIP_COORDINATOR_H_
+
+#import <UIKit/UIKit.h>
+
+#import "ios/showcase/common/coordinator.h"
+
+@interface SCStripCoordinator : NSObject<Coordinator>
+// Redefined to be a UINavigationController.
+@property(nonatomic, weak) UINavigationController* baseViewController;
+@end
+
+#endif  // IOS_SHOWCASE_STRIP_SC_STRIP_COORDINATOR_H_

ios/showcase/strip/sc_strip_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/showcase/strip/sc_strip_coordinator.h"
+
+#import "ios/chrome/browser/ui/actions/tab_strip_actions.h"
+#import "ios/chrome/browser/ui/strip/strip_container_view_controller.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@interface SCStripCoordinator ()
+@property(nonatomic, strong) StripContainerViewController* viewController;
+@end
+
+@implementation SCStripCoordinator
+@synthesize baseViewController = _baseViewController;
+@synthesize viewController = _viewController;
+
+- (void)start {
+  UIViewController* blackViewController = [[UIViewController alloc] init];
+  blackViewController.view.backgroundColor = [UIColor blackColor];
+
+  UIViewController* greenViewController =
+      [self viewControllerWithButtonTitle:@"toggleStrip"
+                                   action:@selector(toggleTabStrip:)];
+  greenViewController.view.backgroundColor = [UIColor greenColor];
+
+  self.viewController = [[StripContainerViewController alloc] init];
+  self.viewController.title = @"Tab strip container";
+  self.viewController.stripViewController = blackViewController;
+  self.viewController.contentViewController = greenViewController;
+  self.baseViewController.navigationBar.translucent = NO;
+  [self.baseViewController pushViewController:self.viewController animated:YES];
+}
+
+- (UIViewController*)viewControllerWithButtonTitle:(NSString*)title
+                                            action:(SEL)action {
+  UIViewController* viewController = [[UIViewController alloc] init];
+  UIButton* button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
+  [button setFrame:CGRectMake(10, 10, 80, 50)];
+  [button setTitle:title forState:UIControlStateNormal];
+  [viewController.view addSubview:button];
+  [button addTarget:nil
+                action:action
+      forControlEvents:UIControlEventTouchUpInside];
+  return viewController;
+}
+
+@end