Replace deprecated base::NonThreadSafe in android_webview in favor of SequenceChecker.

android_webview/browser/renderer_host/aw_render_view_host_ext.h

 // Copyright (c) 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.
 
 #ifndef ANDROID_WEBVIEW_BROWSER_RENDER_HOST_RENDER_VIEW_HOST_EXT_H_
 #define ANDROID_WEBVIEW_BROWSER_RENDER_HOST_RENDER_VIEW_HOST_EXT_H_
 
 #include "content/public/browser/web_contents_observer.h"
 
 #include "android_webview/common/aw_hit_test_data.h"
 #include "base/callback_forward.h"
 #include "base/macros.h"
-#include "base/threading/non_thread_safe.h"
+#include "base/sequence_checker.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/geometry/point_f.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/geometry/size_f.h"
 
 namespace android_webview {
 
 class AwRenderViewHostExtClient {
  public:
   // Called when the RenderView page scale changes.
   virtual void OnWebLayoutPageScaleFactorChanged(float page_scale_factor) = 0;
   virtual void OnWebLayoutContentsSizeChanged(
       const gfx::Size& contents_size) = 0;
 
  protected:
   virtual ~AwRenderViewHostExtClient() {}
 };
 
 // Provides RenderViewHost wrapper functionality for sending WebView-specific
 // IPC messages to the renderer and from there to WebKit.
-class AwRenderViewHostExt : public content::WebContentsObserver,
-                            public base::NonThreadSafe {
+class AwRenderViewHostExt : public content::WebContentsObserver {
  public:
 
   // To send receive messages to a RenderView we take the WebContents instance,
   // as it internally handles RenderViewHost instances changing underneath us.
   AwRenderViewHostExt(
       AwRenderViewHostExtClient* client, content::WebContents* contents);
   ~AwRenderViewHostExt() override;
 
   // |result| will be invoked with the outcome of the request.
   typedef base::Callback<void(bool)> DocumentHasImagesResult;
@@ skipping 64 matching lines @@
   // *current* RVH.
   std::map<int, DocumentHasImagesResult> image_requests_callback_map_;
 
   // Master copy of hit test data on the browser side. This is updated
   // as a result of DoHitTest called explicitly or when the FocusedNodeChanged
   // is called in AwRenderViewExt.
   AwHitTestData last_hit_test_data_;
 
   bool has_new_hit_test_data_;
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   DISALLOW_COPY_AND_ASSIGN(AwRenderViewHostExt);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_RENDER_HOST_RENDER_VIEW_HOST_EXT_H_