Remove WebToolbarDelegate from GoogleLandingDataSource.

ios/chrome/browser/ui/ntp/google_landing_controller.mm

Index: ios/chrome/browser/ui/ntp/google_landing_controller.mm
diff --git a/ios/chrome/browser/ui/ntp/google_landing_controller.mm b/ios/chrome/browser/ui/ntp/google_landing_controller.mm
index 6775b127da0f93e592919a3ce43b1795027ca2ac..fec88c927791fbd7f0c0012658f79acf5ef8f831 100644
--- a/ios/chrome/browser/ui/ntp/google_landing_controller.mm
+++ b/ios/chrome/browser/ui/ntp/google_landing_controller.mm
@@ -193,6 +193,12 @@ const CGFloat kMostVisitedPaddingIPadFavicon = 24;
 // The number of tabs to show in the google landing fake toolbar.
 @property(nonatomic, assign) int tabCount;
 
+// |YES| if the google landing toolbar can show the forward arrow.

[rohitrao (ping after 24h), 2017/04/28 10:39:59]

Perhaps mention somewhere that these two values are cached because they need to
be pushed into the header view, and the header view may not currently exist.

[justincohen, 2017/04/28 13:23:04]

Done.

+@property(nonatomic, assign) BOOL canGoForward;
+
+// |YES| if the google landing toolbar can show the back arrow.
+@property(nonatomic, assign) BOOL canGoBack;
+
 // iPhone landscape uses a slightly different layout for the doodle and search
 // field frame. Returns the proper frame from |frames| based on orientation,
 // centered in the view.
@@ -263,6 +269,8 @@ const CGFloat kMostVisitedPaddingIPadFavicon = 24;
 @synthesize promoCanShow = _promoCanShow;
 @synthesize maximumMostVisitedSitesShown = _maximumMostVisitedSitesShown;
 @synthesize tabCount = _tabCount;
+@synthesize canGoForward = _canGoForward;
+@synthesize canGoBack = _canGoBack;
 @synthesize voiceSearchIsEnabled = _voiceSearchIsEnabled;
 
 - (void)loadView {
@@ -1000,6 +1008,8 @@ const CGFloat kMostVisitedPaddingIPadFavicon = 24;
         // hidden.
         [_headerView addToolbarWithDataSource:self.dataSource];
         [_headerView setToolbarTabCount:self.tabCount];
+        [_headerView setCanGoForward:self.canGoForward];
+        [_headerView setCanGoBack:self.canGoBack];
       }
       [_supplementaryViews addObject:_headerView];
     }
@@ -1494,4 +1504,13 @@ const CGFloat kMostVisitedPaddingIPadFavicon = 24;
   [_headerView setToolbarTabCount:self.tabCount];
 }
 
+- (void)setCanGoForward:(BOOL)canGoForward {
+  _canGoForward = canGoForward;
+  [_headerView setCanGoForward:self.canGoForward];
+}
+
+- (void)setCanGoBack:(BOOL)canGoBack {
+  _canGoBack = canGoBack;
+  [_headerView setCanGoBack:self.canGoBack];
+}
 @end