[android_webview] Fix UAF in request interception code.

android_webview/browser/net/android_stream_reader_url_request_job.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_NATIVE_ANDROID_STREAM_READER_URL_REQUEST_JOB_H_
 #define ANDROID_WEBVIEW_NATIVE_ANDROID_STREAM_READER_URL_REQUEST_JOB_H_
 
 #include <string>
 
 #include "base/android/scoped_java_ref.h"
@@ skipping 23 matching lines @@
 
 // A request job that reads data from a Java InputStream.
 class AndroidStreamReaderURLRequestJob : public net::URLRequestJob {
  public:
   /*
    * We use a delegate so that we can share code for this job in slightly
    * different contexts.
    */
   class Delegate {
    public:
+    // Called from the IO thread when the Job is about to start.
+    virtual void OnStart() = 0;
+
     // This method is called from a worker thread, not from the IO thread.
     virtual scoped_ptr<android_webview::InputStream> OpenInputStream(
         JNIEnv* env,
         const GURL& url) = 0;
 
     // This method is called on the Job's thread if the result of calling
     // OpenInputStream was null.
     // Setting the |restart| parameter to true will cause the request to be
     // restarted with a new job.
     virtual void OnInputStreamOpenFailed(
@@ skipping 58 matching lines @@
   scoped_ptr<net::HttpResponseInfo> response_info_;
   scoped_ptr<Delegate> delegate_;
   scoped_refptr<InputStreamReaderWrapper> input_stream_reader_wrapper_;
   base::WeakPtrFactory<AndroidStreamReaderURLRequestJob> weak_factory_;
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(AndroidStreamReaderURLRequestJob);
 };
 
 #endif  // ANDROID_WEBVIEW_NATIVE_ANDROID_STREAM_READER_URL_REQUEST_JOB_H_