Add the shadow below the toolbar

The toolbar has a shadown below it.

Bug: 791469
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Iaf6ee9fe5190d2c4d5b6243bca3282d01ecba7ca
Reviewed-on: https://chromium-review.googlesource.com/806175
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521654}

ios/chrome/browser/ui/toolbar/clean/BUILD.gn

@@ -62,6 +62,7 @@ source_set("toolbar_ui") {
   deps = [
     ":toolbar_components_ui",
     "//base",
+    "//ios/chrome/app/theme",
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui/activity_services/requirements",
     "//ios/chrome/browser/ui/bubble",

ios/chrome/browser/ui/toolbar/clean/toolbar_view_controller.mm

@@ -22,6 +22,7 @@
 #import "ios/chrome/browser/ui/toolbar/public/web_toolbar_controller_constants.h"
 #import "ios/chrome/browser/ui/uikit_ui_util.h"
 #import "ios/chrome/browser/ui/util/constraints_ui_util.h"
+#include "ios/chrome/grit/ios_theme_resources.h"
 #import "ios/third_party/material_components_ios/src/components/ProgressView/src/MaterialProgressView.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
@@ -46,6 +47,8 @@
 @property(nonatomic, assign) BOOL voiceSearchEnabled;
 @property(nonatomic, strong) MDCProgressView* progressBar;
 @property(nonatomic, strong) UIStackView* locationBarContainerStackView;
+// The shadow below the toolbar. Lazily instantiated.
+@property(nonatomic, strong) UIImageView* shadowView;
 // Background view, used to display the incognito NTP background color on the
 // toolbar.
 @property(nonatomic, strong) UIView* backgroundView;
@@ -87,25 +90,11 @@
 @synthesize voiceSearchEnabled = _voiceSearchEnabled;
 @synthesize progressBar = _progressBar;
 @synthesize locationBarContainerStackView = _locationBarContainerStackView;
+@synthesize shadowView = _shadowView;
 @synthesize expandedToolbarConstraints = _expandedToolbarConstraints;
 @synthesize topSafeAnchor = _topSafeAnchor;
 @synthesize regularToolbarConstraints = _regularToolbarConstraints;
 
-#pragma mark - Properties accessor
-
-- (UIView*)backgroundView {
-  if (!_backgroundView) {
-    _backgroundView = [[UIView alloc] initWithFrame:CGRectZero];
-    _backgroundView.translatesAutoresizingMaskIntoConstraints = NO;
-    _backgroundView.backgroundColor =
-        [UIColor colorWithWhite:kNTPBackgroundColorBrightnessIncognito
-                          alpha:1.0];
-    [self.view insertSubview:_backgroundView atIndex:0];
-    AddSameConstraints(self.view, _backgroundView);
-  }
-  return _backgroundView;
-}
-
 #pragma mark - Public
 
 - (instancetype)initWithDispatcher:
@@ -192,6 +181,7 @@
   [self setUpToolbarStackView];
   [self setUpLocationBarContainerView];
   [self.view addSubview:self.stackView];
+  [self.view addSubview:self.shadowView];
   [self.view addSubview:self.progressBar];
   [self setConstraints];
 }
@@ -257,6 +247,17 @@
   ];
   [NSLayoutConstraint activateConstraints:progressBarConstraints];
 
+  // Shadow constraints.
+  [NSLayoutConstraint activateConstraints:@[
+    [self.shadowView.topAnchor constraintEqualToAnchor:self.view.bottomAnchor],
+    [self.shadowView.leadingAnchor
+        constraintEqualToAnchor:self.view.leadingAnchor],
+    [self.shadowView.trailingAnchor
+        constraintEqualToAnchor:self.view.trailingAnchor],
+    [self.shadowView.heightAnchor
+        constraintEqualToConstant:kToolbarShadowHeight],
+  ]];
+
   // StackView constraints. The main Toolbar StackView.
   NSArray* stackViewConstraints = @[
     [self.stackView.heightAnchor
@@ -613,6 +614,19 @@
 
 #pragma mark - Setters & Getters.
 
+- (UIView*)backgroundView {
+  if (!_backgroundView) {
+    _backgroundView = [[UIView alloc] initWithFrame:CGRectZero];
+    _backgroundView.translatesAutoresizingMaskIntoConstraints = NO;
+    _backgroundView.backgroundColor =
+        [UIColor colorWithWhite:kNTPBackgroundColorBrightnessIncognito
+                          alpha:1.0];
+    [self.view insertSubview:_backgroundView atIndex:0];
+    AddSameConstraints(self.view, _backgroundView);
+  }
+  return _backgroundView;
+}
+
 - (NSLayoutYAxisAnchor*)topSafeAnchor {
   if (!_topSafeAnchor) {
     if (@available(iOS 11, *)) {
@@ -671,6 +685,16 @@
   _locationBarView = view;
 }
 
+- (UIImageView*)shadowView {
+  if (!_shadowView) {
+    _shadowView = [[UIImageView alloc] init];
+    _shadowView.translatesAutoresizingMaskIntoConstraints = NO;
+    _shadowView.userInteractionEnabled = NO;
+    _shadowView.image = NativeImage(IDR_IOS_TOOLBAR_SHADOW);
+  }
+  return _shadowView;
+}
+
 #pragma mark - Private
 
 // Sets the progress of the progressBar to 1 then hides it.

ios/chrome/browser/ui/toolbar/public/toolbar_controller_constants.h

@@ -67,6 +67,9 @@ extern const LayoutOffset kButtonFadeOutXOffset;
 // a popover anchored to it.
 extern const CGFloat kPopoverAnchorHorizontalPadding;
 
+// Height of the shadow displayed below the toolbar.
+extern const CGFloat kToolbarShadowHeight;
+
 // Toolbar style.  Determines which button images are used.
 enum ToolbarControllerStyle {
   ToolbarControllerStyleLightMode = 0,

ios/chrome/browser/ui/toolbar/public/toolbar_controller_constants.mm

@@ -28,6 +28,8 @@ const NSInteger kFontSizeTenTabsOrMore = 9;
 
 const NSUInteger kTransitionLayerCapacity = 11;
 
+const CGFloat kToolbarShadowHeight = 2;
+
 // Macros for creating CGRects of height H, origin (0,0), with the portrait
 // width of phone/pad devices.
 // clang-format off