[iOS][MF] Creates action table view cell

Creates a new UITableViewCell to show user credentials in a table view.
The design is according to the specs for Manual Fallback, which can be
found in:
https://folio.googleplex.com/ntp/Autofill/Autofill%20Manual%20Fallback

Bug: 845472
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: Iaa916c36dfb9ca2a567c904c4ab536b037840077
Reviewed-on: https://chromium-review.googlesource.com/1179756
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584691}

ios/chrome/browser/ui/autofill/manual_fill/action_cell.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_AUTOFILL_MANUAL_FILL_ACTION_CELL_H_
+#define IOS_CHROME_BROWSER_UI_AUTOFILL_MANUAL_FILL_ACTION_CELL_H_
+
+#import <UIKit/UIKit.h>
+
+// A table view cell which contains a button and holds an action block, which
+// is called when the button is touched.
+@interface ManualFillActionCell : UITableViewCell
+
+// Updates the cell with the passed title and action block.
+- (void)setUpWithTitle:(NSString*)title action:(void (^)(void))action;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_AUTOFILL_MANUAL_FILL_ACTION_CELL_H_

ios/chrome/browser/ui/autofill/manual_fill/action_cell.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/autofill/manual_fill/action_cell.h"
+
+#import "ios/chrome/browser/ui/autofill/manual_fill/uicolor_manualfill.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 {
+// Left and right margins of the cell contents.
+static const CGFloat sideMargins = 16;
+// The base multiplier for the top and bottom margins.  This number multiplied
+// by the font size plus the base margins will give similar results to
+// |constraintEqualToSystemSpacingBelowAnchor:|.
+static const CGFloat iOS10MarginFontMultiplier = 1.18;
+// The base top margin, only used in iOS 10. Refer to
+// |iOS10MarginFontMultiplier| for how it is used.
+static const CGFloat iOS10BaseTopMargin = 24;
+// The base bottom margin, only used in iOS 10. Refer to
+// |iOS10MarginFontMultiplier| for how it is used.
+static const CGFloat iOS10BaseBottomMargin = 6;
+// The multiplier for the base system spacing at the top margin.
+static const CGFloat TopBaseSystemSpacingMultiplier = 1.78;
+// The multiplier for the base system spacing at the bottom margin.
+static const CGFloat BottomBaseSystemSpacingMultiplier = 2.26;
+}  // namespace
+
+@interface ManualFillActionCell ()
+// The action block to be called when the user taps the title button.
+@property(nonatomic, copy) void (^action)(void);
+// The title button of this cell.
+@property(nonatomic, strong) UIButton* titleButton;
+@end
+
+@implementation ManualFillActionCell
+@synthesize action = _action;
+@synthesize titleButton = _titleButton;
+
+#pragma mark - Public
+
+- (void)setUpWithTitle:(NSString*)title action:(void (^)(void))action {
+  if (self.contentView.subviews.count == 0) {
+    [self createView];
+  }
+  [self.titleButton setTitle:title forState:UIControlStateNormal];
+  self.action = action;
+}
+
+- (void)prepareForReuse {
+  [super prepareForReuse];
+  self.action = nil;
+}
+
+#pragma mark - Private
+
+- (void)createView {
+  self.selectionStyle = UITableViewCellSelectionStyleNone;
+
+  self.titleButton = [[UIButton alloc] init];
+  [self.titleButton setTitleColor:UIColor.cr_manualFillTintColor
+                         forState:UIControlStateNormal];
+  self.titleButton.translatesAutoresizingMaskIntoConstraints = NO;
+  self.titleButton.titleLabel.font =
+      [UIFont preferredFontForTextStyle:UIFontTextStyleBody];
+  self.titleButton.titleLabel.adjustsFontForContentSizeCategory = YES;
+  [self.titleButton addTarget:self
+                       action:@selector(userDidTapTitleButton:)
+             forControlEvents:UIControlEventTouchUpInside];
+  self.titleButton.titleLabel.lineBreakMode = NSLineBreakByTruncatingTail;
+  [self.contentView addSubview:self.titleButton];
+  id<LayoutGuideProvider> safeArea =
+      SafeAreaLayoutGuideForView(self.contentView);
+
+  NSArray* verticalConstraints;
+  if (@available(iOS 11, *)) {
+    // Multipliers of these constraints are calculated based on a 24 base
+    // system spacing.
+    verticalConstraints = @[
+      // Vertical constraints.
+      [self.titleButton.firstBaselineAnchor
+          constraintEqualToSystemSpacingBelowAnchor:self.contentView.topAnchor
+                                         multiplier:
+                                             TopBaseSystemSpacingMultiplier],
+      [self.contentView.bottomAnchor
+          constraintEqualToSystemSpacingBelowAnchor:self.titleButton
+                                                        .lastBaselineAnchor
+                                         multiplier:
+                                             BottomBaseSystemSpacingMultiplier],
+    ];
+  } else {
+    CGFloat pointSize = self.titleButton.titleLabel.font.pointSize;
+    // These margins are based on the design size and the current point size.
+    // The multipliers were selected by manually testing the different system
+    // font sizes.
+    CGFloat marginTop =
+        iOS10BaseTopMargin + pointSize * iOS10MarginFontMultiplier;
+    CGFloat marginBottom =
+        iOS10BaseBottomMargin + pointSize * iOS10MarginFontMultiplier;
+
+    verticalConstraints = @[
+      [self.titleButton.firstBaselineAnchor
+          constraintEqualToAnchor:self.contentView.topAnchor
+                         constant:marginTop],
+      [self.contentView.bottomAnchor
+          constraintEqualToAnchor:self.titleButton.lastBaselineAnchor
+                         constant:marginBottom],
+    ];
+  }
+  [NSLayoutConstraint activateConstraints:verticalConstraints];
+  // Horizontal constraints.
+  [NSLayoutConstraint activateConstraints:@[
+    [self.titleButton.leadingAnchor
+        constraintEqualToAnchor:safeArea.leadingAnchor
+                       constant:sideMargins],
+    [safeArea.trailingAnchor
+        constraintGreaterThanOrEqualToAnchor:self.titleButton.trailingAnchor
+                                    constant:sideMargins],
+  ]];
+}
+
+- (void)userDidTapTitleButton:(UIButton*)sender {
+  if (self.action) {
+    self.action();
+  }
+}
+
+@end

ios/chrome/browser/ui/autofill/manual_fill/uicolor_manualfill.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_AUTOFILL_MANUAL_FILL_UICOLOR_MANUALFILL_H_
+#define IOS_CHROME_BROWSER_UI_AUTOFILL_MANUAL_FILL_UICOLOR_MANUALFILL_H_
+
+#import <UIKit/UIKit.h>
+
+@interface UIColor (ManualFill)
+// Color to set in interactable elements for manual fill (0.1, 0.45, 0.91 RGB).
+@property(class, nonatomic, readonly) UIColor* cr_manualFillTintColor;
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_AUTOFILL_MANUAL_FILL_UICOLOR_MANUALFILL_H_

ios/chrome/browser/ui/autofill/manual_fill/uicolor_manualfill.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/autofill/manual_fill/uicolor_manualfill.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@implementation UIColor (ManualFill)
+
++ (UIColor*)cr_manualFillTintColor {
+  static UIColor* color =
+      [UIColor colorWithRed:0.10 green:0.45 blue:0.91 alpha:1.0];
+  return color;
+}
+
+@end