Revert of [ios] Removed back-forward navigation API from CRWWebController.

ios/web/web_state/ui/crw_web_controller.mm

Index: ios/web/web_state/ui/crw_web_controller.mm
diff --git a/ios/web/web_state/ui/crw_web_controller.mm b/ios/web/web_state/ui/crw_web_controller.mm
index bbf10276e74fd59475dff1462110eabae63182d7..7e3f9d70073e15f3f05a195993d34c54202339ca 100644
--- a/ios/web/web_state/ui/crw_web_controller.mm
+++ b/ios/web/web_state/ui/crw_web_controller.mm
@@ -1379,6 +1379,14 @@
   return defaultImage;
 }
 
+- (BOOL)canGoBack {
+  return _webStateImpl->GetNavigationManagerImpl().CanGoBack();
+}
+
+- (BOOL)canGoForward {
+  return _webStateImpl->GetNavigationManagerImpl().CanGoForward();
+}
+
 - (CGPoint)scrollPosition {
   CGPoint position = CGPointMake(0.0, 0.0);
   if (!self.webScrollView)
@@ -2271,6 +2279,14 @@
     case web::PAGE_LOADED:
       break;
   }
+}
+
+- (void)goBack {
+  [self goDelta:-1];
+}
+
+- (void)goForward {
+  [self goDelta:1];
 }
 
 - (void)goDelta:(int)delta {
@@ -3016,13 +3032,13 @@
 
 - (BOOL)handleWindowHistoryBackMessage:(base::DictionaryValue*)message
                                context:(NSDictionary*)context {
-  [self goDelta:-1];
+  [self goBack];
   return YES;
 }
 
 - (BOOL)handleWindowHistoryForwardMessage:(base::DictionaryValue*)message
                                   context:(NSDictionary*)context {
-  [self goDelta:1];
+  [self goForward];
   return YES;
 }