Make the UI an observer of downloads.

chrome/browser/android/chrome_web_contents_delegate_android.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 CHROME_BROWSER_ANDROID_CHROME_WEB_CONTENTS_DELEGATE_ANDROID_H_
 #define CHROME_BROWSER_ANDROID_CHROME_WEB_CONTENTS_DELEGATE_ANDROID_H_
 
 #include <jni.h>
 
 #include "content/components/web_contents_delegate_android/web_contents_delegate_android.h"
@@ skipping 37 matching lines @@
                          bool final_update) OVERRIDE;
   virtual void FindMatchRectsReply(content::WebContents* web_contents,
                                    int version,
                                    const std::vector<gfx::RectF>& rects,
                                    const gfx::RectF& active_rect) OVERRIDE;
   virtual content::JavaScriptDialogCreator*
   GetJavaScriptDialogCreator() OVERRIDE;
   virtual bool CanDownload(content::RenderViewHost* source,
                            int request_id,
                            const std::string& request_method) OVERRIDE;
-  virtual void OnStartDownload(content::WebContents* source,
-                               content::DownloadItem* download) OVERRIDE;
 
  private:
   // NotificationObserver implementation.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
   void OnFindResultAvailable(content::WebContents* web_contents,
                              const FindNotificationDetails* find_result);
 
   content::NotificationRegistrar notification_registrar_;
 };
 
 // Register the native methods through JNI.
 bool RegisterChromeWebContentsDelegateAndroid(JNIEnv* env);
 
 }  // namespace android
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_ANDROID_CHROME_WEB_CONTENTS_DELEGATE_ANDROID_H_