Moves overscroll code out of the ios_internal namespace.

ios/chrome/browser/tabs/tab.mm

 // Copyright 2012 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/tabs/tab.h"
 
 #import <CoreLocation/CoreLocation.h>
 #import <UIKit/UIKit.h>
 
 #include <utility>
@@ skipping 997 matching lines @@
     return;
 
   // Lazily create a OverscrollActionsController.
   // The check for overscrollActionsControllerDelegate is necessary to avoid
   // recreating a OverscrollActionsController during teardown.
   if (!overscrollActionsController_) {
     overscrollActionsController_.reset(
         [[OverscrollActionsController alloc] init]);
     [self.webController addObserver:overscrollActionsController_];
   }
-  ios_internal::OverscrollStyle style =
-      ios_internal::OverscrollStyle::REGULAR_PAGE_NON_INCOGNITO;
+  OverscrollStyle style = OverscrollStyle::REGULAR_PAGE_NON_INCOGNITO;
   if (browserState_->IsOffTheRecord()) {
-    style = ios_internal::OverscrollStyle::REGULAR_PAGE_INCOGNITO;
+    style = OverscrollStyle::REGULAR_PAGE_INCOGNITO;
   }
   [overscrollActionsController_ setStyle:style];
   [overscrollActionsController_
       setDelegate:overscrollActionsControllerDelegate];
   overscrollActionsControllerDelegate_.reset(
       overscrollActionsControllerDelegate);
 }
 
 - (void)updateTitle:(NSString*)title {
   web::NavigationItem* item = [self navigationManager]->GetVisibleItem();
@@ skipping 1420 matching lines @@
 
 - (TabModel*)parentTabModel {
   return parentTabModel_;
 }
 
 - (FormInputAccessoryViewController*)inputAccessoryViewController {
   return inputAccessoryViewController_.get();
 }
 
 @end