Avoid a string copy in URLRequestResourceBundleJob::GetData().

net/url_request/url_request_simple_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 NET_URL_REQUEST_URL_REQUEST_SIMPLE_JOB_H_
 #define NET_URL_REQUEST_URL_REQUEST_SIMPLE_JOB_H_
 
 #include <string>
 
+#include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/strings/string_piece.h"
 #include "net/base/completion_callback.h"
 #include "net/base/net_export.h"
 #include "net/url_request/url_range_request_job.h"
 
+namespace base {
+class RefCountedMemory;
+}
+
 namespace net {
 
 class URLRequest;
 
 class NET_EXPORT URLRequestSimpleJob : public URLRangeRequestJob {
  public:
   URLRequestSimpleJob(URLRequest* request, NetworkDelegate* network_delegate);
 
   void Start() override;
   bool ReadRawData(IOBuffer* buf, int buf_size, int* bytes_read) override;
   bool GetMimeType(std::string* mime_type) const override;
   bool GetCharset(std::string* charset) override;
 
  protected:
   ~URLRequestSimpleJob() override;
 
   // Subclasses must override the way response data is determined.

[mmenke, 2014/11/17 15:54:10]

Should mention subclasses must override only one or the other.

[Jeffrey Yasskin, 2014/11/17 17:16:23]

Done.

   // The return value should be:
   //  - OK if data is obtained;
   //  - ERR_IO_PENDING if async processing is needed to finish obtaining data.
   //    This is the only case when |callback| should be called after
   //    completion of the operation. In other situations |callback| should
   //    never be called;
   //  - any other ERR_* code to indicate an error. This code will be used
   //    as the error code in the URLRequestStatus when the URLRequest
   //    is finished.
   virtual int GetData(std::string* mime_type,
                       std::string* charset,
                       std::string* data,
-                      const CompletionCallback& callback) const = 0;
+                      const CompletionCallback& callback) const;
+  // Similar to GetData(), except *data can share ownership of the bytes instead

[mmenke, 2014/11/17 15:54:10]

nit:  |*data| or *|data|.

[Jeffrey Yasskin, 2014/11/17 17:16:23]

Done.

+  // of copying them into a std::string.
+  virtual int GetRefCountedData(std::string* mime_type,
+                                std::string* charset,
+                                scoped_refptr<base::RefCountedMemory>* data,
+                                const CompletionCallback& callback) const;
 
  protected:
   void StartAsync();
 
  private:
   void OnGetDataCompleted(int result);
 
   HttpByteRange byte_range_;
   std::string mime_type_;
   std::string charset_;
-  std::string data_;
+  scoped_refptr<base::RefCountedMemory> data_;
   int data_offset_;
   base::WeakPtrFactory<URLRequestSimpleJob> weak_factory_;
 };
 
 }  // namespace net
 
 #endif  // NET_URL_REQUEST_URL_REQUEST_SIMPLE_JOB_H_