Add Overscroll Actions support to SadTabViewController.

This CL adds OverscrollActionsController to SadTabViewController.
OverscrollActionsController requires UIScrollView to work, so
SadTabViewController creates a dummy scroll view to hold SadTabView.

Bug: 901563
Change-Id: I564ed10b807d774b891d86c21cda58435a5681c2
Reviewed-on: https://chromium-review.googlesource.com/c/1332390Reviewed-by: Kurt Horimoto <kkhorimoto@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607780}

ios/chrome/browser/ui/browser_view_controller.mm

@@ -2413,6 +2413,7 @@ applicationCommandEndpoint:(id<ApplicationCommands>)applicationCommandEndpoint {
                       browserState:_browserState];
     sadTabCoordinator.dispatcher = self.dispatcher;
     sadTabCoordinator.delegate = self;
+    sadTabCoordinator.overscrollDelegate = self;
     _sadTabCoordinator = sadTabCoordinator;
   } else {
     SadTabLegacyCoordinator* sadTabCoordinator =

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

@@ -20,6 +20,7 @@ source_set("sad_tab") {
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui/colors",
     "//ios/chrome/browser/ui/commands",
+    "//ios/chrome/browser/ui/overscroll_actions",
     "//ios/chrome/browser/ui/util",
     "//ios/third_party/material_components_ios",
     "//ios/third_party/material_roboto_font_loader_ios",
@@ -54,6 +55,7 @@ source_set("coordinator") {
     "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/ui/commands",
     "//ios/chrome/browser/ui/coordinators:chrome_coordinators",
+    "//ios/chrome/browser/ui/overscroll_actions",
     "//ios/chrome/browser/ui/util",
     "//ios/chrome/browser/web",
     "//ios/chrome/browser/web:tab_helper_delegates",

ios/chrome/browser/ui/sad_tab/sad_tab_coordinator.h

@@ -10,6 +10,7 @@
 
 @protocol ApplicationCommands;
 @protocol BrowserCommands;
+@protocol OverscrollActionsControllerDelegate;
 @class SadTabCoordinator;
 
 @protocol SadTabCoordinatorDelegate
@@ -24,6 +25,11 @@
 
 @property(nonatomic, weak) id<SadTabCoordinatorDelegate> delegate;
 
+// Required to support Overscroll Actions UI, which is displayed when Sad Tab is
+// pulled down.
+@property(nonatomic, weak) id<OverscrollActionsControllerDelegate>
+    overscrollDelegate;
+
 @property(nonatomic, readonly) UIViewController* viewController;
 
 // YES if page load for this URL has failed more than once.

ios/chrome/browser/ui/sad_tab/sad_tab_coordinator.mm

@@ -8,6 +8,7 @@
 #import "ios/chrome/browser/ui/commands/application_commands.h"
 #import "ios/chrome/browser/ui/commands/browser_commands.h"
 #import "ios/chrome/browser/ui/commands/open_new_tab_command.h"
+#import "ios/chrome/browser/ui/overscroll_actions/overscroll_actions_controller.h"
 #import "ios/chrome/browser/ui/sad_tab/sad_tab_view_controller.h"
 #import "ios/chrome/browser/web/sad_tab_tab_helper.h"
 #import "ios/chrome/common/ui_util/constraints_ui_util.h"
@@ -25,6 +26,7 @@
 @implementation SadTabCoordinator
 @synthesize dispatcher = _dispatcher;
 @synthesize delegate = _delegate;
+@synthesize overscrollDelegate = _overscrollDelegate;
 @synthesize viewController = _viewController;
 @synthesize repeatedFailure = _repeatedFailure;
 
@@ -34,6 +36,7 @@
 
   _viewController = [[SadTabViewController alloc] init];
   _viewController.delegate = self;
+  _viewController.overscrollDelegate = self.overscrollDelegate;
   _viewController.offTheRecord = self.browserState->IsOffTheRecord();
   _viewController.repeatedFailure = _repeatedFailure;
 
@@ -54,6 +57,12 @@
   _viewController = nil;
 }
 
+- (void)setOverscrollDelegate:
+    (id<OverscrollActionsControllerDelegate>)delegate {
+  _viewController.overscrollDelegate = delegate;
+  _overscrollDelegate = delegate;
+}
+
 #pragma mark - SadTabViewDelegate
 
 - (void)sadTabViewControllerShowReportAnIssue:

ios/chrome/browser/ui/sad_tab/sad_tab_view_controller.h

@@ -8,6 +8,7 @@
 #import <UIKit/UIKit.h>
 
 class GURL;
+@protocol OverscrollActionsControllerDelegate;
 @class SadTabViewController;
 
 @protocol SadTabViewControllerDelegate<NSObject>
@@ -28,6 +29,11 @@ class GURL;
 
 @property(nonatomic, weak) id<SadTabViewControllerDelegate> delegate;
 
+// Required to support Overscroll Actions UI, which is displayed when Sad Tab is
+// pulled down.
+@property(nonatomic, weak) id<OverscrollActionsControllerDelegate>
+    overscrollDelegate;
+
 // YES if page load for this URL has failed more than once.
 @property(nonatomic, assign) BOOL repeatedFailure;
 

ios/chrome/browser/ui/sad_tab/sad_tab_view_controller.mm

@@ -4,7 +4,11 @@
 
 #import "ios/chrome/browser/ui/sad_tab/sad_tab_view_controller.h"
 
+#include <CoreGraphics/CoreGraphics.h>
+
+#import "ios/chrome/browser/ui/overscroll_actions/overscroll_actions_controller.h"
 #import "ios/chrome/browser/ui/sad_tab/sad_tab_view.h"
+#import "ios/chrome/browser/ui/util/uikit_ui_util.h"
 #import "ios/chrome/common/ui_util/constraints_ui_util.h"
 #include "url/gurl.h"
 
@@ -16,6 +20,14 @@
 
 @property(nonatomic) SadTabView* sadTabView;
 
+// Scroll view is required by OverscrollActionsController and will be a parent
+// view of the sad tab view.
+@property(nonatomic) UIScrollView* scrollView;
+
+// Allows supporting Overscroll Actions UI, which is displayed when Sad Tab is
+// pulled down.
+@property(nonatomic) OverscrollActionsController* overscrollActionsController;
+
 @end
 
 @implementation SadTabViewController
@@ -23,21 +35,58 @@
 @synthesize repeatedFailure = _repeatedFailure;
 @synthesize offTheRecord = _offTheRecord;
 @synthesize sadTabView = _sadTabView;
+@synthesize scrollView = _scrollView;
+@synthesize overscrollActionsController = _overscrollActionsController;
+@synthesize overscrollDelegate = _overscrollDelegate;
 
 #pragma mark - UIViewController
 
 - (void)viewDidLoad {
   [super viewDidLoad];
 
+  // Scroll view is required by OverscrollActionsController and will be a parent
+  // view of the sad tab view.
+  self.scrollView = [[UIScrollView alloc] init];
+  self.scrollView.showsVerticalScrollIndicator = NO;
+  [self.view addSubview:self.scrollView];
+  self.scrollView.translatesAutoresizingMaskIntoConstraints = NO;
+  AddSameConstraints(self.scrollView, self.view);
+
+  // SadTabView is a child of the scroll view as reqired by
+  // OverscrollActionsController.
   SadTabViewMode mode =
       self.repeatedFailure ? SadTabViewMode::FEEDBACK : SadTabViewMode::RELOAD;
   self.sadTabView =
       [[SadTabView alloc] initWithMode:mode offTheRecord:self.offTheRecord];
-  self.sadTabView.translatesAutoresizingMaskIntoConstraints = NO;
   self.sadTabView.delegate = self;
-  [self.view addSubview:self.sadTabView];
+  [self.scrollView addSubview:self.sadTabView];
+
+  // OverscrollActionsController allows Overscroll Actions UI.
+  self.overscrollActionsController =
+      [[OverscrollActionsController alloc] initWithScrollView:self.scrollView];
+  self.overscrollActionsController.delegate = self.overscrollDelegate;
+  self.scrollView.delegate = self.overscrollActionsController;
+  OverscrollStyle style = self.offTheRecord
+                              ? OverscrollStyle::REGULAR_PAGE_INCOGNITO
+                              : OverscrollStyle::REGULAR_PAGE_NON_INCOGNITO;
+  [self.overscrollActionsController setStyle:style];
+  [self updateOverscrollActionsState];
+}
+
+- (void)viewDidLayoutSubviews {
+  [super viewDidLayoutSubviews];
 
-  AddSameConstraints(self.sadTabView, self.view);
+  // In order to allow UIScollView to scroll vertically, the height of the
+  // content should be taller than the hight of the scroll view.
+  CGRect newFrame = self.view.bounds;
+  newFrame.size.height += 1;
+  self.sadTabView.frame = newFrame;
+  [self.scrollView setContentSize:newFrame.size];
+}
+
+- (void)traitCollectionDidChange:(UITraitCollection*)previousTraitCollection {
+  [super traitCollectionDidChange:previousTraitCollection];
+  [self updateOverscrollActionsState];
 }
 
 #pragma mark - SadTabViewDelegate
@@ -55,6 +104,17 @@
   [self.delegate sadTabViewControllerReload:self];
 }
 
+#pragma mark - Private
+
+// Enables or disables overscroll actions.
+- (void)updateOverscrollActionsState {
+  if (IsSplitToolbarMode(self)) {
+    [self.overscrollActionsController enableOverscrollActions];
+  } else {
+    [self.overscrollActionsController disableOverscrollActions];
+  }
+}
+
 @end
 
 #pragma mark -