[iOS][Translate] Compact translate infobar view

video: https://drive.google.com/file/d/1rRJgtGsgFPsFgcoUCwqcYT-dHDKguuhk/view?usp=sharing

Starting from the leading edge, it features an icon followed by the source
and the target languages. Toggling between the languages results in the
page to be translated or the translation to be reverted. At the trailing
edge, the infobar features an options button that opens a popup menu that
allows changing translate preferences followed by a close button to dismiss
the infobar. The view hierarchy is as follows:
TranslateInfobarView ->
TranslateInfobarTabStripView ->
TranslateInfobarTabView

Bug: 910994
Change-Id: Icc9d06f43a4a91ba0ec967ce3e9b372b5e9b9bfb
Reviewed-on: https://chromium-review.googlesource.com/c/1426014
Commit-Queue: Moe Ahmadi <mahmadi@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#625681}

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

@@ -41,6 +41,15 @@ source_set("translate_ui") {
     "language_selection_provider.h",
     "language_selection_view_controller.h",
     "language_selection_view_controller.mm",
+    "translate_infobar_language_tab_strip_view.h",
+    "translate_infobar_language_tab_strip_view.mm",
+    "translate_infobar_language_tab_strip_view_delegate.h",
+    "translate_infobar_language_tab_view.h",
+    "translate_infobar_language_tab_view.mm",
+    "translate_infobar_language_tab_view_delegate.h",
+    "translate_infobar_view.h",
+    "translate_infobar_view.mm",
+    "translate_infobar_view_delegate.h",
     "translate_notification_delegate.h",
     "translate_notification_handler.h",
     "translate_notification_presenter.h",
@@ -50,7 +59,14 @@ source_set("translate_ui") {
     "//base",
     "//components/strings:components_strings",
     "//ios/chrome/browser",
+    "//ios/chrome/browser/ui/colors",
+    "//ios/chrome/browser/ui/infobars:infobars_ui",
+    "//ios/chrome/browser/ui/toolbar/buttons",
+    "//ios/chrome/browser/ui/translate/resources:translate_dismiss",
+    "//ios/chrome/browser/ui/translate/resources:translate_icon",
+    "//ios/chrome/browser/ui/translate/resources:translate_options",
     "//ios/chrome/browser/ui/util",
+    "//ios/chrome/common/ui_util",
     "//ios/third_party/material_components_ios",
     "//ui/base",
   ]

ios/chrome/browser/ui/translate/resources/BUILD.gn

+# Copyright 2019 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("//build/config/ios/asset_catalog.gni")
+
+imageset("translate_icon") {
+  sources = [
+    "translate_icon.imageset/Contents.json",
+    "translate_icon.imageset/translate_icon.png",
+    "translate_icon.imageset/translate_icon@2x.png",
+    "translate_icon.imageset/translate_icon@3x.png",
+  ]
+}
+
+imageset("translate_options") {
+  sources = [
+    "translate_options.imageset/Contents.json",
+    "translate_options.imageset/translate_options.png",
+    "translate_options.imageset/translate_options@2x.png",
+    "translate_options.imageset/translate_options@3x.png",
+  ]
+}
+
+imageset("translate_dismiss") {
+  sources = [
+    "translate_dismiss.imageset/Contents.json",
+    "translate_dismiss.imageset/translate_dismiss.png",
+    "translate_dismiss.imageset/translate_dismiss@2x.png",
+    "translate_dismiss.imageset/translate_dismiss@3x.png",
+  ]
+}

ios/chrome/browser/ui/translate/resources/translate_dismiss.imageset/Contents.json

+{
+    "images": [
+        {
+            "idiom": "universal",
+            "scale": "1x",
+            "filename": "translate_dismiss.png"
+        },
+        {
+            "idiom": "universal",
+            "scale": "2x",
+            "filename": "translate_dismiss@2x.png"
+        },
+        {
+            "idiom": "universal",
+            "scale": "3x",
+            "filename": "translate_dismiss@3x.png"
+        }
+    ],
+    "info": {
+        "version": 1,
+        "author": "xcode"
+    }
+}

ios/chrome/browser/ui/translate/resources/translate_icon.imageset/Contents.json

+{
+    "images": [
+        {
+            "idiom": "universal",
+            "scale": "1x",
+            "filename": "translate_icon.png"
+        },
+        {
+            "idiom": "universal",
+            "scale": "2x",
+            "filename": "translate_icon@2x.png"
+        },
+        {
+            "idiom": "universal",
+            "scale": "3x",
+            "filename": "translate_icon@3x.png"
+        }
+    ],
+    "info": {
+        "version": 1,
+        "author": "xcode"
+    }
+}

ios/chrome/browser/ui/translate/resources/translate_options.imageset/Contents.json

+{
+    "images": [
+        {
+            "idiom": "universal",
+            "scale": "1x",
+            "filename": "translate_options.png"
+        },
+        {
+            "idiom": "universal",
+            "scale": "2x",
+            "filename": "translate_options@2x.png"
+        },
+        {
+            "idiom": "universal",
+            "scale": "3x",
+            "filename": "translate_options@3x.png"
+        }
+    ],
+    "info": {
+        "version": 1,
+        "author": "xcode"
+    }
+}

ios/chrome/browser/ui/translate/translate_infobar_language_tab_strip_view.h

+// Copyright 2019 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_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_STRIP_VIEW_H_
+#define IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_STRIP_VIEW_H_
+
+#import <UIKit/UIKit.h>
+
+#import "ios/chrome/browser/ui/translate/translate_infobar_language_tab_view.h"
+
+@protocol TranslateInfobarLanguageTabStripViewDelegate;
+
+// A view containing a scrollable tab strip featuring the source and the target
+// language tabs. When a language tab is tapped, it is scrolled into view, if
+// necessary.
+@interface TranslateInfobarLanguageTabStripView : UIView
+
+// Source language name.
+@property(nonatomic, copy) NSString* sourceLanguage;
+
+// Target language name.
+@property(nonatomic, copy) NSString* targetLanguage;
+
+// State of the source language tab.
+@property(nonatomic)
+    TranslateInfobarLanguageTabViewState sourceLanguageTabState;
+
+// State of the target language tab.
+@property(nonatomic)
+    TranslateInfobarLanguageTabViewState targetLanguageTabState;
+
+// Delegate object that gets notified if user taps the source or the target
+// language tabs.
+@property(nonatomic, weak) id<TranslateInfobarLanguageTabStripViewDelegate>
+    delegate;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_STRIP_VIEW_H_

ios/chrome/browser/ui/translate/translate_infobar_language_tab_strip_view.mm

+// Copyright 2019 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/translate/translate_infobar_language_tab_strip_view.h"
+
+#import "ios/chrome/browser/ui/translate/translate_infobar_language_tab_strip_view_delegate.h"
+#import "ios/chrome/browser/ui/translate/translate_infobar_language_tab_view_delegate.h"
+#import "ios/chrome/browser/ui/translate/translate_infobar_view.h"
+#import "ios/chrome/common/ui_util/constraints_ui_util.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace {
+
+// The point where the gradient on the leading edge of the scroll view stops.
+CGFloat kScrollViewLeadingGradientStop = 0.025;
+
+// The point where the gradient on the trailing edge of the scroll view starts.
+CGFloat kScrollViewTrailingGradientStart = 0.975;
+
+}  // namespace
+
+@interface TranslateInfobarLanguageTabStripView () <
+    TranslateInfobarLanguageTabViewDelegate,
+    UIScrollViewDelegate>
+
+// Scroll view holding the source and the target language tab views.
+@property(nonatomic, weak) UIScrollView* languagesScrollView;
+
+// Used for the fading effect on the edges of the scroll view.
+@property(nonatomic, weak) CAGradientLayer* gradientLayer;
+
+// Source language tab view.
+@property(nonatomic, weak) TranslateInfobarLanguageTabView* sourceLanguageTab;
+
+// Target language tab view.
+@property(nonatomic, weak) TranslateInfobarLanguageTabView* targetLanguageTab;
+
+@end
+
+@implementation TranslateInfobarLanguageTabStripView
+
+#pragma mark - UIView
+
+- (void)willMoveToSuperview:(UIView*)newSuperview {
+  // Create and add subviews the first time this moves to a superview.
+  if (newSuperview && !self.subviews.count) {
+    [self setupSubviews];
+  }
+  [super willMoveToSuperview:newSuperview];
+}
+
+- (void)layoutSubviews {
+  [super layoutSubviews];
+
+  // Scroll the scroll view so that the selected language tab is visible.
+  if (self.sourceLanguageTabState ==
+      TranslateInfobarLanguageTabViewStateSelected) {
+    [self.languagesScrollView scrollRectToVisible:self.sourceLanguageTab.frame
+                                         animated:YES];
+  } else if (self.targetLanguageTabState ==
+             TranslateInfobarLanguageTabViewStateSelected) {
+    [self.languagesScrollView scrollRectToVisible:self.targetLanguageTab.frame
+                                         animated:YES];
+  }
+
+  [self updateLanguageScrollViewGradient];
+}
+
+#pragma mark - Properties
+
+- (void)setSourceLanguage:(NSString*)sourceLanguage {
+  _sourceLanguage = sourceLanguage;
+  self.sourceLanguageTab.title = sourceLanguage;
+
+  [self updateLanguageScrollViewGradient];
+}
+
+- (void)setTargetLanguage:(NSString*)targetLanguage {
+  _targetLanguage = targetLanguage;
+  self.targetLanguageTab.title = targetLanguage;
+
+  [self updateLanguageScrollViewGradient];
+}
+
+- (void)setSourceLanguageTabState:
+    (TranslateInfobarLanguageTabViewState)sourceLanguageTabState {
+  _sourceLanguageTabState = sourceLanguageTabState;
+
+  self.sourceLanguageTab.state = sourceLanguageTabState;
+}
+
+- (void)setTargetLanguageTabState:
+    (TranslateInfobarLanguageTabViewState)targetLanguageTabState {
+  _targetLanguageTabState = targetLanguageTabState;
+
+  self.targetLanguageTab.state = targetLanguageTabState;
+}
+
+#pragma mark - UIScrollViewDelegate
+
+- (void)scrollViewDidScroll:(UIScrollView*)scrollView {
+  [self updateLanguageScrollViewGradient];
+}
+
+#pragma mark - TranslateInfobarLanguageTabViewDelegate
+
+- (void)translateInfobarTabViewDidTap:(TranslateInfobarLanguageTabView*)sender {
+  [self.languagesScrollView scrollRectToVisible:sender.frame animated:YES];
+
+  if (sender == self.targetLanguageTab) {
+    [self.delegate translateInfobarTabStripViewDidTapTargetLangugage:self];
+  } else {
+    [self.delegate translateInfobarTabStripViewDidTapSourceLangugage:self];
+  }
+}
+
+#pragma mark - Private
+
+- (void)setupSubviews {
+  UIScrollView* languagesScrollView = [[UIScrollView alloc] init];
+  self.languagesScrollView = languagesScrollView;
+  self.languagesScrollView.translatesAutoresizingMaskIntoConstraints = NO;
+  self.languagesScrollView.showsVerticalScrollIndicator = NO;
+  self.languagesScrollView.showsHorizontalScrollIndicator = NO;
+  self.languagesScrollView.canCancelContentTouches = YES;
+  self.languagesScrollView.bounces = NO;
+  self.languagesScrollView.delegate = self;
+  [self addSubview:self.languagesScrollView];
+
+  self.gradientLayer = [CAGradientLayer layer];
+  self.gradientLayer.colors =
+      [NSArray arrayWithObjects:(id)[[UIColor clearColor] CGColor],
+                                (id)[[UIColor whiteColor] CGColor],
+                                (id)[[UIColor whiteColor] CGColor],
+                                (id)[[UIColor clearColor] CGColor], nil];
+  // The following two lines make the gradient horizontal.
+  self.gradientLayer.startPoint = CGPointMake(0.0, 0.5);
+  self.gradientLayer.endPoint = CGPointMake(1.0, 0.5);
+  self.languagesScrollView.layer.mask = self.gradientLayer;
+
+  TranslateInfobarLanguageTabView* sourceLanguageTab =
+      [[TranslateInfobarLanguageTabView alloc] init];
+  self.sourceLanguageTab = sourceLanguageTab;
+  self.sourceLanguageTab.translatesAutoresizingMaskIntoConstraints = NO;
+  self.sourceLanguageTab.title = self.sourceLanguage;
+  self.sourceLanguageTab.delegate = self;
+  [self.languagesScrollView addSubview:self.sourceLanguageTab];
+
+  TranslateInfobarLanguageTabView* targetLanguageTab =
+      [[TranslateInfobarLanguageTabView alloc] init];
+  self.targetLanguageTab = targetLanguageTab;
+  self.targetLanguageTab.translatesAutoresizingMaskIntoConstraints = NO;
+  self.targetLanguageTab.title = self.targetLanguage;
+  self.targetLanguageTab.delegate = self;
+  [self.languagesScrollView addSubview:self.targetLanguageTab];
+
+  ApplyVisualConstraintsWithMetrics(
+      @[
+        @"H:|[scrollView]|",
+        @"H:|[sourceLanguage][targetLanguage]|",
+        @"V:|[scrollView(infobarHeight)]|",
+        @"V:|[sourceLanguage(infobarHeight)]|",
+        @"V:|[targetLanguage(infobarHeight)]|",
+      ],
+      @{
+        @"scrollView" : self.languagesScrollView,
+        @"sourceLanguage" : self.sourceLanguageTab,
+        @"targetLanguage" : self.targetLanguageTab,
+      },
+      @{
+        @"infobarHeight" : @(kInfobarHeight),
+      });
+}
+
+// Updates the scroll view's gradient locations based on whether or not the
+// scroll view has content under the leading fold, trailing fold, or both.
+- (void)updateLanguageScrollViewGradient {
+  // Lay out the scroll view's subviews if needed.
+  [self.languagesScrollView layoutIfNeeded];
+
+  CGFloat scrollViewWidth = CGRectGetWidth(self.languagesScrollView.frame);
+  CGFloat contentWidth = self.languagesScrollView.contentSize.width;
+  CGFloat scrollOffset = self.languagesScrollView.contentOffset.x;
+  BOOL hasContentUnderLeadingFold = (scrollOffset > 0);
+  BOOL hasContentUnderTrailingFold =
+      (scrollOffset + scrollViewWidth < contentWidth);
+  self.gradientLayer.locations = @[
+    @0, hasContentUnderLeadingFold ? @(kScrollViewLeadingGradientStop) : @0,
+    hasContentUnderTrailingFold ? @(kScrollViewTrailingGradientStart) : @1, @1
+  ];
+
+  // Disable animation; or updating the gradient's frame will be animated.
+  [CATransaction begin];
+  [CATransaction setDisableActions:YES];
+
+  // Update the gradient's frame.
+  self.gradientLayer.frame = CGRectMake(
+      scrollOffset, 0, CGRectGetWidth(self.languagesScrollView.bounds),
+      CGRectGetHeight(self.languagesScrollView.bounds));
+
+  // Reenable animation.
+  [CATransaction commit];
+}
+
+@end

ios/chrome/browser/ui/translate/translate_infobar_language_tab_strip_view_delegate.h

+// Copyright 2019 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_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_STRIP_VIEW_DELEGATE_H_
+#define IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_STRIP_VIEW_DELEGATE_H_
+
+#import <Foundation/Foundation.h>
+
+// A protocol implemented by a delegate of TranslateInfobarLanguageTabStripView.
+@protocol TranslateInfobarLanguageTabStripViewDelegate
+
+// Notifies the delegate that user tapped the source language tab.
+- (void)translateInfobarTabStripViewDidTapSourceLangugage:
+    (TranslateInfobarLanguageTabStripView*)sender;
+
+// Notifies the delegate that user tapped the target language tab.
+- (void)translateInfobarTabStripViewDidTapTargetLangugage:
+    (TranslateInfobarLanguageTabStripView*)sender;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_STRIP_VIEW_DELEGATE_H_

ios/chrome/browser/ui/translate/translate_infobar_language_tab_view.h

+// Copyright 2019 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_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_VIEW_H_
+#define IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_VIEW_H_
+
+#import <UIKit/UIKit.h>
+
+// States in which the language tab can be.
+typedef NS_ENUM(NSInteger, TranslateInfobarLanguageTabViewState) {
+  TranslateInfobarLanguageTabViewStateDefault,
+  TranslateInfobarLanguageTabViewStateSelected,
+  TranslateInfobarLanguageTabViewStateLoading,
+};
+
+@protocol TranslateInfobarLanguageTabViewDelegate;
+
+// The language tab view featuring a label. It can be in a default, selected, or
+// loading state. In the selected state the label is highlighted and in the
+// loading state the label is replaced by an activity indicator.
+@interface TranslateInfobarLanguageTabView : UIView
+
+// Title of the language tab.
+@property(nonatomic, copy) NSString* title;
+
+// State of the language tab.
+@property(nonatomic) TranslateInfobarLanguageTabViewState state;
+
+// Delegate object that gets notified if user taps the view.
+@property(nonatomic, weak) id<TranslateInfobarLanguageTabViewDelegate> delegate;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_VIEW_H_

ios/chrome/browser/ui/translate/translate_infobar_language_tab_view.mm

+// Copyright 2019 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/translate/translate_infobar_language_tab_view.h"
+
+#include "base/logging.h"
+#import "ios/chrome/browser/ui/colors/MDCPalette+CrAdditions.h"
+#import "ios/chrome/browser/ui/translate/translate_infobar_language_tab_strip_view.h"
+#import "ios/chrome/browser/ui/translate/translate_infobar_language_tab_view_delegate.h"
+#import "ios/chrome/browser/ui/util/uikit_ui_util.h"
+#import "ios/chrome/common/ui_util/constraints_ui_util.h"
+#import "ios/third_party/material_components_ios/src/components/ActivityIndicator/src/MaterialActivityIndicator.h"
+#import "ios/third_party/material_components_ios/src/components/Buttons/src/MaterialButtons.h"
+#import "ios/third_party/material_components_ios/src/components/Typography/src/MaterialTypography.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace {
+
+// Size of the activity indicator.
+const CGFloat kActivityIndicatorSize = 24;
+
+// Radius of the activity indicator.
+const CGFloat kActivityIndicatorRadius = 10;
+
+// Duration of the animation to make the activity indicator visible.
+const NSTimeInterval kActivityIndicatorVisbilityAnimationDuration = 0.4;
+
+// Title color of the action buttons in RGB.
+const int kButtonTitleColor = 0x4285f4;
+
+// Padding for contents of the button.
+const CGFloat kButtonPadding = 12;
+
+}  // namespace
+
+@interface TranslateInfobarLanguageTabView ()
+
+// Button subview providing the tappable area.
+@property(nonatomic, weak) MDCFlatButton* button;
+
+// Activity indicator replacing the button when in loading state.
+@property(nonatomic, weak) MDCActivityIndicator* activityIndicator;
+
+@end
+
+@implementation TranslateInfobarLanguageTabView
+
+#pragma mark - UIView
+
+- (void)willMoveToSuperview:(UIView*)newSuperview {
+  // Create and add subviews the first time this moves to a superview.
+  if (newSuperview && !self.subviews.count) {
+    [self setupSubviews];
+  }
+  [super willMoveToSuperview:newSuperview];
+}
+
+#pragma mark - Properties
+
+- (void)setTitle:(NSString*)title {
+  _title = title;
+  [self.button setTitle:title forState:UIControlStateNormal];
+}
+
+- (void)setState:(TranslateInfobarLanguageTabViewState)state {
+  _state = state;
+
+  if (state == TranslateInfobarLanguageTabViewStateLoading) {
+    [self.activityIndicator startAnimating];
+    // Animate showing the activity indicator and hiding the button. Otherwise
+    // the ripple effect on the button won't be seen.
+    [UIView animateWithDuration:kActivityIndicatorVisbilityAnimationDuration
+                     animations:^{
+                       self.activityIndicator.hidden = NO;
+                       self.button.hidden = YES;
+                     }];
+  } else {
+    self.button.hidden = NO;
+    self.activityIndicator.hidden = YES;
+    [self.activityIndicator stopAnimating];
+
+    [self.button setTitleColor:[self titleColor] forState:UIControlStateNormal];
+  }
+}
+
+#pragma mark - Private
+
+- (void)setupSubviews {
+  MDCActivityIndicator* activityIndicator = [[MDCActivityIndicator alloc] init];
+  self.activityIndicator = activityIndicator;
+  self.activityIndicator.translatesAutoresizingMaskIntoConstraints = NO;
+  self.activityIndicator.cycleColors =
+      @[ [[MDCPalette cr_bluePalette] tint500] ];
+  [self.activityIndicator setRadius:kActivityIndicatorRadius];
+  self.activityIndicator.hidden = YES;  // Initially hidden.
+  [self addSubview:self.activityIndicator];
+
+  [NSLayoutConstraint activateConstraints:@[
+    [self.activityIndicator.heightAnchor
+        constraintEqualToConstant:kActivityIndicatorSize],
+  ]];
+  AddSameCenterConstraints(self, self.activityIndicator);
+
+  MDCFlatButton* button = [[MDCFlatButton alloc] init];
+  self.button = button;
+  self.button.translatesAutoresizingMaskIntoConstraints = NO;
+  [self.button setUnderlyingColorHint:[UIColor blackColor]];
+  self.button.contentEdgeInsets = UIEdgeInsetsMake(
+      kButtonPadding, kButtonPadding, kButtonPadding, kButtonPadding);
+  self.button.titleLabel.adjustsFontSizeToFitWidth = YES;
+  self.button.titleLabel.minimumScaleFactor = 0.6f;
+  [self.button setTitle:self.title forState:UIControlStateNormal];
+  self.button.uppercaseTitle = NO;
+  [self.button
+      setTitleFont:[UIFont preferredFontForTextStyle:UIFontTextStyleHeadline]
+          forState:UIControlStateNormal];
+  [self.button setTitleColor:[self titleColor] forState:UIControlStateNormal];
+  self.button.inkColor = [[MDCPalette greyPalette] tint300];
+  [self.button addTarget:self
+                  action:@selector(buttonWasTapped)
+        forControlEvents:UIControlEventTouchUpInside];
+  [self addSubview:self.button];
+
+  AddSameConstraints(self, self.button);
+}
+
+// Returns the button's title color depending on the state.
+- (UIColor*)titleColor {
+  return self.state == TranslateInfobarLanguageTabViewStateSelected
+             ? UIColorFromRGB(kButtonTitleColor)
+             : [[MDCPalette greyPalette] tint600];
+}
+
+- (void)buttonWasTapped {
+  [self.delegate translateInfobarTabViewDidTap:self];
+}
+
+@end

ios/chrome/browser/ui/translate/translate_infobar_language_tab_view_delegate.h

+// Copyright 2019 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_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_VIEW_DELEGATE_H_
+#define IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_VIEW_DELEGATE_H_
+
+#import <Foundation/Foundation.h>
+
+// A protocol implemented by a delegate of TranslateInfobarLanguageTabView.
+@protocol TranslateInfobarLanguageTabViewDelegate
+
+// Notifies the delegate that user tapped the view.
+- (void)translateInfobarTabViewDidTap:(TranslateInfobarLanguageTabView*)sender;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_LANGUAGE_TAB_VIEW_DELEGATE_H_

ios/chrome/browser/ui/translate/translate_infobar_view.h

+// Copyright 2019 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_TRANSLATE_TRANSLATE_INFOBAR_VIEW_H_
+#define IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_VIEW_H_
+
+#import <UIKit/UIKit.h>
+
+#include <vector>
+
+// States in which the infobar can be.
+typedef NS_ENUM(NSInteger, TranslateInfobarViewState) {
+  TranslateInfobarViewStateBeforeTranslate,
+  TranslateInfobarViewStateTranslating,
+  TranslateInfobarViewStateAfterTranslate,
+};
+
+// Height of the infobar.
+extern const CGFloat kInfobarHeight;
+
+@protocol TranslateInfobarViewDelegate;
+
+// An infobar for translating the page. Starting from the leading edge, it
+// features an icon followed by the source and the target languages. Toggling
+// between the languages results in the page to be translated or the translation
+// to be reverted. At the trailing edge, the infobar features an options button
+// that opens a popup menu that allows changing translate preferences followed
+// by a dismiss button to close the infobar.
+@interface TranslateInfobarView : UIView
+
+// Source language name.
+@property(nonatomic, copy) NSString* sourceLanguage;
+
+// Target language name.
+@property(nonatomic, copy) NSString* targetLanguage;
+
+// Infobar's state.
+@property(nonatomic) TranslateInfobarViewState state;
+
+// Delegate object that gets notified if user taps the source language tab, the
+// target language tab, the options button, or the dismiss button.
+@property(nonatomic, weak) id<TranslateInfobarViewDelegate> delegate;
+
+// Updates the infobar UI when a popup menu is displayed or dismissed.
+- (void)updateUIForPopUpMenuDisplayed:(BOOL)displayed;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_VIEW_H_

ios/chrome/browser/ui/translate/translate_infobar_view_delegate.h

+// Copyright 2019 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_TRANSLATE_TRANSLATE_INFOBAR_VIEW_DELEGATE_H_
+#define IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_VIEW_DELEGATE_H_
+
+#import <Foundation/Foundation.h>
+
+// A protocol implemented by a delegate of TranslateInfobarView.
+@protocol TranslateInfobarViewDelegate
+
+// Notifies the delegate that user tapped the source language button.
+- (void)translateInfobarViewDidTapSourceLangugage:(TranslateInfobarView*)sender;
+
+// Notifies the delegate that user tapped the target language button.
+- (void)translateInfobarViewDidTapTargetLangugage:(TranslateInfobarView*)sender;
+
+// Notifies the delegate that user tapped the options button.
+- (void)translateInfobarViewDidTapOptions:(TranslateInfobarView*)sender;
+
+// Notifies the delegate that user tapped the dismiss button.
+- (void)translateInfobarViewDidTapDismiss:(TranslateInfobarView*)sender;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TRANSLATE_TRANSLATE_INFOBAR_VIEW_DELEGATE_H_