Remove base's implicit_cast.

chrome/browser/ui/views/apps/chrome_native_app_window_views_mac.mm

 // Copyright 2015 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 "chrome/browser/ui/views/apps/chrome_native_app_window_views_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #import "base/mac/scoped_nsobject.h"
 #import "base/mac/sdk_forward_declarations.h"
@@ skipping 20 matching lines @@
 
 @implementation StartResizeNotificationObserver
 
 - (id)initForNativeAppWindow:(ChromeNativeAppWindowViewsMac*)nativeAppWindow {
   if ((self = [super init])) {
     nativeAppWindow_ = nativeAppWindow;
     [[NSNotificationCenter defaultCenter]
         addObserver:self
            selector:@selector(onWindowWillStartLiveResize:)
                name:NSWindowWillStartLiveResizeNotification
-             object:implicit_cast<ui::BaseWindow*>(nativeAppWindow)
+             object:static_cast<ui::BaseWindow*>(nativeAppWindow)
                         ->GetNativeWindow()];
   }
   return self;
 }
 
 - (void)onWindowWillStartLiveResize:(NSNotification*)notification {
   nativeAppWindow_->OnWindowWillStartLiveResize();
 }
 
 - (void)stopObserving {
@@ skipping 131 matching lines @@
   ChromeNativeAppWindowViews::Hide();
 }
 
 void ChromeNativeAppWindowViewsMac::UnhideWithoutActivation() {
   if (is_hidden_with_app_) {
     apps::ExtensionAppShimHandler::UnhideWithoutActivationForWindow(
         app_window());
     is_hidden_with_app_ = false;
   }
 }