Update {virtual,override,final} to follow C++11 style.

android_webview/native/aw_contents_io_thread_client_impl.cc

Index: android_webview/native/aw_contents_io_thread_client_impl.cc
diff --git a/android_webview/native/aw_contents_io_thread_client_impl.cc b/android_webview/native/aw_contents_io_thread_client_impl.cc
index 4f7ce44b2947e8c34efbc0ab46f8203578c70925..69003ae3a1a186766f5172987bbc52d5879b7dd7 100644
--- a/android_webview/native/aw_contents_io_thread_client_impl.cc
+++ b/android_webview/native/aw_contents_io_thread_client_impl.cc
@@ -116,9 +116,9 @@ class ClientMapEntryUpdater : public content::WebContentsObserver {
   ClientMapEntryUpdater(JNIEnv* env, WebContents* web_contents,
                         jobject jdelegate);
 
-  virtual void RenderFrameCreated(RenderFrameHost* render_frame_host) override;
-  virtual void RenderFrameDeleted(RenderFrameHost* render_frame_host) override;
-  virtual void WebContentsDestroyed() override;
+  void RenderFrameCreated(RenderFrameHost* render_frame_host) override;
+  void RenderFrameDeleted(RenderFrameHost* render_frame_host) override;
+  void WebContentsDestroyed() override;
 
  private:
   JavaObjectWeakGlobalRef jdelegate_;