11.diff

diff --git a/ios/chrome/browser/ui/toolbar/BUILD.gn b/ios/chrome/browser/ui/toolbar/BUILD.gn
index 9ac010b..c2986eb 100644
--- a/ios/chrome/browser/ui/toolbar/BUILD.gn
+++ b/ios/chrome/browser/ui/toolbar/BUILD.gn
@@ -17,7 +17,6 @@
     "toolbar_controller_constants.mm",
     "toolbar_coordinator.h",
     "toolbar_coordinator.mm",
-    "toolbar_frame_delegate.h",
     "toolbar_model_delegate_ios.h",
     "toolbar_model_delegate_ios.mm",
     "toolbar_model_impl_ios.h",
@@ -28,6 +27,7 @@
     "toolbar_tools_menu_button.mm",
     "toolbar_view.h",
     "toolbar_view.mm",
+    "toolbar_view_delegate.h",
     "tools_menu_button_observer_bridge.h",
     "tools_menu_button_observer_bridge.mm",
     "web_toolbar_controller.h",
diff --git a/ios/chrome/browser/ui/toolbar/toolbar_frame_delegate.h b/ios/chrome/browser/ui/toolbar/toolbar_frame_delegate.h
deleted file mode 100644
index 4def7ba..0000000
--- a/ios/chrome/browser/ui/toolbar/toolbar_frame_delegate.h
+++ /dev/null
@@ -1,18 +0,0 @@
-// Copyright 2017 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_TOOLBAR_TOOLBAR_FRAME_DELEGATE_H_
-#define IOS_CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_FRAME_DELEGATE_H_
-
-#import <Foundation/Foundation.h>
-
-// Create a thin wrapper around UIImageView to catch frame change and window
-// events.
-@protocol ToolbarFrameDelegate<NSObject>
-- (void)frameDidChangeFrame:(CGRect)newFrame fromFrame:(CGRect)oldFrame;
-- (void)windowDidChange;
-- (void)traitCollectionDidChange;
-@end
-
-#endif  // IOS_CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_FRAME_DELEGATE_H_
diff --git a/ios/chrome/browser/ui/toolbar/toolbar_view.h b/ios/chrome/browser/ui/toolbar/toolbar_view.h
index 8712d73..d37320b 100644
--- a/ios/chrome/browser/ui/toolbar/toolbar_view.h
+++ b/ios/chrome/browser/ui/toolbar/toolbar_view.h
@@ -9,7 +9,7 @@
 
 #import "ios/chrome/browser/ui/util/relaxed_bounds_constraints_hittest.h"
 
-@protocol ToolbarFrameDelegate;
+@protocol ToolbarViewDelegate;
 
 @interface ToolbarView : UIView<RelaxedBoundsConstraintsHitTestSupport>
 - (instancetype)initWithNibName:(NSString*)name
@@ -17,7 +17,7 @@
 - (instancetype)initWithCoder:(NSCoder*)coder NS_UNAVAILABLE;
 
 // The delegate used to handle frame changes and windows events.
-@property(nonatomic, weak) id<ToolbarFrameDelegate> delegate;
+@property(nonatomic, weak) id<ToolbarViewDelegate> delegate;
 // Records whether or not the toolbar is currently involved in a transition
 // animation.
 @property(nonatomic, assign, getter=isAnimatingTransition)
diff --git a/ios/chrome/browser/ui/toolbar/toolbar_view.mm b/ios/chrome/browser/ui/toolbar/toolbar_view.mm
index ef4a858..0c2797a 100644
--- a/ios/chrome/browser/ui/toolbar/toolbar_view.mm
+++ b/ios/chrome/browser/ui/toolbar/toolbar_view.mm
@@ -5,7 +5,7 @@
 #import "ios/chrome/browser/ui/toolbar/toolbar_view.h"
 
 #import "ios/chrome/browser/ui/toolbar/toolbar_controller_base_feature.h"
-#import "ios/chrome/browser/ui/toolbar/toolbar_frame_delegate.h"
+#import "ios/chrome/browser/ui/toolbar/toolbar_view_delegate.h"
 
 @implementation ToolbarView
 
@@ -57,10 +57,9 @@
   return hitView;
 }
 
-- (void)setFrame:(CGRect)frame {
-  CGRect oldFrame = self.frame;
-  [super setFrame:frame];
-  [delegate_ frameDidChangeFrame:frame fromFrame:oldFrame];
+- (void)layoutSubviews {
+  [super layoutSubviews];
+  [delegate_ toolbarDidLayout];
 }
 
 - (void)didMoveToWindow {
diff --git a/ios/chrome/browser/ui/toolbar/toolbar_view_delegate.h b/ios/chrome/browser/ui/toolbar/toolbar_view_delegate.h
new file mode 100644
index 0000000..e7e85d2
--- /dev/null
+++ b/ios/chrome/browser/ui/toolbar/toolbar_view_delegate.h
@@ -0,0 +1,26 @@
+// Copyright 2017 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_TOOLBAR_TOOLBAR_VIEW_DELEGATE_H_
+#define IOS_CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_VIEW_DELEGATE_H_
+
+#import <Foundation/Foundation.h>
+
+// A delegate protocol to pass UIView information about the toolbar.
+// TODO(crbug.com/683793): Remove this protocol when toolbars are presented via
+// UIViewControllers, as this can already be accomplished through that API.
+@protocol ToolbarViewDelegate<NSObject>
+
+// Called when the toolbar view performs a layout pass.
+- (void)toolbarDidLayout;
+
+// Called when the toolbar view is transferred to a new parent window.
+- (void)windowDidChange;
+
+// Called when the toolbar view's trait collection changes.
+- (void)traitCollectionDidChange;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_VIEW_DELEGATE_H_
diff --git a/ios/chrome/browser/ui/toolbar/web_toolbar_controller.h b/ios/chrome/browser/ui/toolbar/web_toolbar_controller.h
index bc518aa..ecaacf6 100644
--- a/ios/chrome/browser/ui/toolbar/web_toolbar_controller.h
+++ b/ios/chrome/browser/ui/toolbar/web_toolbar_controller.h
@@ -19,7 +19,6 @@
 @protocol ApplicationCommands;
 @protocol BrowserCommands;
 @class Tab;
-@protocol ToolbarFrameDelegate;
 @protocol UrlLoader;
 @protocol WebToolbarDelegate;
 
diff --git a/ios/chrome/browser/ui/toolbar/web_toolbar_controller.mm b/ios/chrome/browser/ui/toolbar/web_toolbar_controller.mm
index 6573de5..15bf92a 100644
--- a/ios/chrome/browser/ui/toolbar/web_toolbar_controller.mm
+++ b/ios/chrome/browser/ui/toolbar/web_toolbar_controller.mm
@@ -56,7 +56,7 @@
 #import "ios/chrome/browser/ui/toolbar/keyboard_assist/toolbar_assistive_keyboard_views.h"
 #import "ios/chrome/browser/ui/toolbar/toolbar_controller+protected.h"
 #import "ios/chrome/browser/ui/toolbar/toolbar_controller_base_feature.h"
-#import "ios/chrome/browser/ui/toolbar/toolbar_frame_delegate.h"
+#import "ios/chrome/browser/ui/toolbar/toolbar_view_delegate.h"
 #import "ios/chrome/browser/ui/toolbar/toolbar_model_ios.h"
 #include "ios/chrome/browser/ui/toolbar/toolbar_resource_macros.h"
 #import "ios/chrome/browser/ui/toolbar/web_toolbar_controller_constants.h"
@@ -100,7 +100,7 @@
                                    LocationBarDelegate,
                                    OmniboxPopupPositioner,
                                    ToolbarAssistiveKeyboardDelegate,
-                                   ToolbarFrameDelegate> {
+                                   ToolbarViewDelegate> {
   // Top-level view for web content.
   UIView* _webToolbar;
   UIButton* _backButton;
@@ -138,6 +138,9 @@
   // reversed.
   ToolbarButtonMode _forwardButtonMode;
 
+  // Keeps track of the last known toolbar frame.
+  CGRect _lastKnownToolbarFrame;
+
   // Keeps track of last known trait collection used by the subviews.
   UITraitCollection* _lastKnownTraitCollection;
 
@@ -1199,12 +1202,14 @@
 }
 
 #pragma mark -
-#pragma mark ToolbarFrameDelegate methods.
+#pragma mark ToolbarViewDelegate methods.
 
-- (void)frameDidChangeFrame:(CGRect)newFrame fromFrame:(CGRect)oldFrame {
-  if (oldFrame.origin.y == newFrame.origin.y)
+- (void)toolbarDidLayout {
+  CGRect frame = self.view.frame;
+  if (CGRectEqualToRect(_lastKnownToolbarFrame, frame))
     return;
-  [self updateToolbarAlphaForFrame:newFrame];
+  [self updateToolbarAlphaForFrame:frame];
+  _lastKnownToolbarFrame = frame;
 }
 
 - (void)windowDidChange {