[Blob] BlobReader class & tests, and removal of all redundant reading.

storage/browser/blob/blob_url_request_job_factory.h

 // Copyright (c) 2011 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 STORAGE_BROWSER_BLOB_BLOB_URL_REQUEST_JOB_FACTORY_H_
 #define STORAGE_BROWSER_BLOB_BLOB_URL_REQUEST_JOB_FACTORY_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_job_factory.h"
 #include "storage/browser/storage_browser_export.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }  // namespace base
 
 namespace storage {
 class FileSystemContext;
 }  // namespace storage
 
 namespace net {
 class URLRequestContext;
 }  // namespace net
 
 namespace storage {
 
-class BlobDataSnapshot;
 class BlobDataHandle;
 class BlobStorageContext;
 
 class STORAGE_EXPORT BlobProtocolHandler
     : public net::URLRequestJobFactory::ProtocolHandler {
  public:
   // A helper to manufacture an URLRequest to retrieve the given blob.
   static scoped_ptr<net::URLRequest> CreateBlobRequest(
       scoped_ptr<BlobDataHandle> blob_data_handle,
       const net::URLRequestContext* request_context,
       net::URLRequest::Delegate* request_delegate);
 
   // This class ignores the request's URL and uses the value given
   // to SetRequestedBlobDataHandle instead.
   static void SetRequestedBlobDataHandle(
       net::URLRequest* request,
       scoped_ptr<BlobDataHandle> blob_data_handle);
 
+  // This gets the handle on the request if it exists.
+  static BlobDataHandle* GetRequestBlobDataHandle(net::URLRequest* request);
+
   BlobProtocolHandler(
       BlobStorageContext* context,
       storage::FileSystemContext* file_system_context,
       const scoped_refptr<base::SingleThreadTaskRunner>& file_task_runner);
   ~BlobProtocolHandler() override;
 
   net::URLRequestJob* MaybeCreateJob(
       net::URLRequest* request,
       net::NetworkDelegate* network_delegate) const override;
 
  private:
-  scoped_ptr<BlobDataSnapshot> LookupBlobData(net::URLRequest* request) const;
+  BlobDataHandle* LookupBlobHandle(net::URLRequest* request) const;
 
   base::WeakPtr<BlobStorageContext> context_;
   const scoped_refptr<storage::FileSystemContext> file_system_context_;
   const scoped_refptr<base::SingleThreadTaskRunner> file_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(BlobProtocolHandler);
 };
 
 }  // namespace storage
 
 #endif  // STORAGE_BROWSER_BLOB_BLOB_URL_REQUEST_JOB_FACTORY_H_