Move UrlFetcher to content. I originally thought that it's only used by chrome code, but turns o...

chrome/common/net/url_fetcher.cc

Index: chrome/common/net/url_fetcher.cc
===================================================================
--- chrome/common/net/url_fetcher.cc	(revision 87381)
+++ chrome/common/net/url_fetcher.cc	(working copy)
@@ -1,1042 +0,0 @@
-// 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.
-
-#include "chrome/common/net/url_fetcher.h"
-
-#include <set>
-
-#include "base/compiler_specific.h"
-#include "base/file_path.h"
-#include "base/file_util_proxy.h"
-#include "base/lazy_instance.h"
-#include "base/memory/scoped_callback_factory.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/message_loop_proxy.h"
-#include "base/platform_file.h"
-#include "base/stl_util-inl.h"
-#include "base/string_util.h"
-#include "base/threading/thread.h"
-#include "content/browser/browser_thread.h"
-#include "googleurl/src/gurl.h"
-#include "net/base/load_flags.h"
-#include "net/base/io_buffer.h"
-#include "net/base/net_errors.h"
-#include "net/base/host_port_pair.h"
-#include "net/http/http_request_headers.h"
-#include "net/http/http_response_headers.h"
-#include "net/url_request/url_request.h"
-#include "net/url_request/url_request_context.h"
-#include "net/url_request/url_request_context_getter.h"
-#include "net/url_request/url_request_throttler_manager.h"
-
-static const int kBufferSize = 4096;
-const int URLFetcher::kInvalidHttpResponseCode = -1;
-
-class URLFetcher::Core
-    : public base::RefCountedThreadSafe<URLFetcher::Core>,
-      public net::URLRequest::Delegate {
- public:
-  // For POST requests, set |content_type| to the MIME type of the content
-  // and set |content| to the data to upload.  |flags| are flags to apply to
-  // the load operation--these should be one or more of the LOAD_* flags
-  // defined in net/base/load_flags.h.
-  Core(URLFetcher* fetcher,
-       const GURL& original_url,
-       RequestType request_type,
-       URLFetcher::Delegate* d);
-
-  // Starts the load.  It's important that this not happen in the constructor
-  // because it causes the IO thread to begin AddRef()ing and Release()ing
-  // us.  If our caller hasn't had time to fully construct us and take a
-  // reference, the IO thread could interrupt things, run a task, Release()
-  // us, and destroy us, leaving the caller with an already-destroyed object
-  // when construction finishes.
-  void Start();
-
-  // Stops any in-progress load and ensures no callback will happen.  It is
-  // safe to call this multiple times.
-  void Stop();
-
-  // Reports that the received content was malformed (i.e. failed parsing
-  // or validation).  This makes the throttling logic that does exponential
-  // back-off when servers are having problems treat the current request as
-  // a failure.  Your call to this method will be ignored if your request is
-  // already considered a failure based on the HTTP response code or response
-  // headers.
-  void ReceivedContentWasMalformed();
-
-  // Overridden from net::URLRequest::Delegate:
-  virtual void OnResponseStarted(net::URLRequest* request);
-  virtual void OnReadCompleted(net::URLRequest* request, int bytes_read);
-
-  URLFetcher::Delegate* delegate() const { return delegate_; }
-  static void CancelAll();
-
- private:
-  friend class base::RefCountedThreadSafe<URLFetcher::Core>;
-
-  class Registry {
-   public:
-    Registry();
-    ~Registry();
-
-    void AddURLFetcherCore(Core* core);
-    void RemoveURLFetcherCore(Core* core);
-
-    void CancelAll();
-
-    int size() const {
-      return fetchers_.size();
-    }
-
-   private:
-    std::set<Core*> fetchers_;
-
-    DISALLOW_COPY_AND_ASSIGN(Registry);
-  };
-
-  // Class TempFileWriter encapsulates all state involved in writing
-  // response bytes to a temporary file. It is only used if
-  // |Core::response_destination_| == TEMP_FILE.
-  class TempFileWriter {
-   public:
-    TempFileWriter(
-        URLFetcher::Core* core,
-        scoped_refptr<base::MessageLoopProxy> file_message_loop_proxy);
-
-    ~TempFileWriter();
-    void CreateTempFile();
-    void DidCreateTempFile(base::PlatformFileError error_code,
-                           base::PassPlatformFile file_handle,
-                           FilePath file_path);
-    void DidCloseTempFile(base::PlatformFileError error_code);
-    void DidReopenTempFile(base::PlatformFileError error_code,
-                           base::PassPlatformFile file_handle,
-                           bool created);
-
-    // Record |num_bytes_| response bytes in |core_->buffer_| to the file.
-    void WriteBuffer(int num_bytes);
-
-    // Called when a write has been done.  Continues writing if there are
-    // any more bytes to write.  Otherwise, initiates a read in core_.
-    void ContinueWrite(base::PlatformFileError error_code,
-                       int bytes_written);
-
-    // Drop ownership of the file at path |temp_file_|. This class
-    // will not delete it or write to it again.
-    void DisownTempFile();
-
-    // Remove any file created.
-    void Destroy();
-
-    const FilePath& temp_file() const { return temp_file_; }
-    int64 total_bytes_written() { return total_bytes_written_; }
-    base::PlatformFileError error_code() const { return error_code_; }
-
-   private:
-    // The URLFetcher::Core which instantiated this class.
-    URLFetcher::Core* core_;
-
-    // The last error encountered on a file operation.  base::PLATFORM_FILE_OK
-    // if no error occurred.
-    base::PlatformFileError error_code_;
-
-    // Callbacks are created for use with base::FileUtilProxy.
-    base::ScopedCallbackFactory<URLFetcher::Core::TempFileWriter>
-        callback_factory_;
-
-    // Message loop on which file opperations should happen.
-    scoped_refptr<base::MessageLoopProxy> file_message_loop_proxy_;
-
-    // Path to the temporary file.  This path is empty when there
-    // is no temp file.
-    FilePath temp_file_;
-
-    // Handle to the temp file.
-    base::PlatformFile temp_file_handle_;
-
-    // We always append to the file.  Track the total number of bytes
-    // written, so that writes know the offset to give.
-    int64 total_bytes_written_;
-
-    // How many bytes did the last Write() try to write?  Needed so
-    // that if not all the bytes get written on a Write(), we can
-    // call Write() again with the rest.
-    int pending_bytes_;
-
-    // When writing, how many bytes from the buffer have been successfully
-    // written so far?
-    int buffer_offset_;
-  };
-
-  virtual ~Core();
-
-  // Wrapper functions that allow us to ensure actions happen on the right
-  // thread.
-  void StartURLRequest();
-  void StartURLRequestWhenAppropriate();
-  void CancelURLRequest();
-  void OnCompletedURLRequest(const net::URLRequestStatus& status);
-  void InformDelegateFetchIsComplete();
-  void NotifyMalformedContent();
-
-  // Deletes the request, removes it from the registry, and removes the
-  // destruction observer.
-  void ReleaseRequest();
-
-  // Returns the max value of exponential back-off release time for
-  // |original_url_| and |url_|.
-  base::TimeTicks GetBackoffReleaseTime();
-
-  void CompleteAddingUploadDataChunk(const std::string& data,
-                                     bool is_last_chunk);
-
-  // Adds a block of data to be uploaded in a POST body. This can only be
-  // called after Start().
-  void AppendChunkToUpload(const std::string& data, bool is_last_chunk);
-
-  // Store the response bytes in |buffer_| in the container indicated by
-  // |response_destination_|. Return true if the write has been
-  // done, and another read can overwrite |buffer_|.  If this function
-  // returns false, it will post a task that will read more bytes once the
-  // write is complete.
-  bool WriteBuffer(int num_bytes);
-
-  // Read response bytes from the request.
-  void ReadResponse();
-
-  URLFetcher* fetcher_;              // Corresponding fetcher object
-  GURL original_url_;                // The URL we were asked to fetch
-  GURL url_;                         // The URL we eventually wound up at
-  RequestType request_type_;         // What type of request is this?
-  net::URLRequestStatus status_;     // Status of the request
-  URLFetcher::Delegate* delegate_;   // Object to notify on completion
-  scoped_refptr<base::MessageLoopProxy> delegate_loop_proxy_;
-                                     // Message loop proxy of the creating
-                                     // thread.
-  scoped_refptr<base::MessageLoopProxy> io_message_loop_proxy_;
-                                     // The message loop proxy for the thread
-                                     // on which the request IO happens.
-  scoped_refptr<base::MessageLoopProxy> file_message_loop_proxy_;
-                                     // The message loop proxy for the thread
-                                     // on which file access happens.
-  scoped_ptr<net::URLRequest> request_;   // The actual request this wraps
-  int load_flags_;                   // Flags for the load operation
-  int response_code_;                // HTTP status code for the request
-  std::string data_;                 // Results of the request, when we are
-                                     // storing the response as a string.
-  scoped_refptr<net::IOBuffer> buffer_;
-                                     // Read buffer
-  scoped_refptr<net::URLRequestContextGetter> request_context_getter_;
-                                     // Cookie/cache info for the request
-  net::ResponseCookies cookies_;     // Response cookies
-  net::HttpRequestHeaders extra_request_headers_;
-  scoped_refptr<net::HttpResponseHeaders> response_headers_;
-  bool was_fetched_via_proxy_;
-  net::HostPortPair socket_address_;
-
-  std::string upload_content_;       // HTTP POST payload
-  std::string upload_content_type_;  // MIME type of POST payload
-  std::string referrer_;             // HTTP Referer header value
-  bool is_chunked_upload_;           // True if using chunked transfer encoding
-
-  // Used to determine how long to wait before making a request or doing a
-  // retry.
-  // Both of them can only be accessed on the IO thread.
-  // We need not only the throttler entry for |original_URL|, but also the one
-  // for |url|. For example, consider the case that URL A redirects to URL B,
-  // for which the server returns a 500 response. In this case, the exponential
-  // back-off release time of URL A won't increase. If we retry without
-  // considering the back-off constraint of URL B, we may send out too many
-  // requests for URL A in a short period of time.
-  scoped_refptr<net::URLRequestThrottlerEntryInterface>
-      original_url_throttler_entry_;
-  scoped_refptr<net::URLRequestThrottlerEntryInterface> url_throttler_entry_;
-
-  // |num_retries_| indicates how many times we've failed to successfully
-  // fetch this URL.  Once this value exceeds the maximum number of retries
-  // specified by the owner URLFetcher instance, we'll give up.
-  int num_retries_;
-
-  // True if the URLFetcher has been cancelled.
-  bool was_cancelled_;
-
-  // Since GetBackoffReleaseTime() can only be called on the IO thread, we cache
-  // its value to be used by OnCompletedURLRequest on the creating thread.
-  base::TimeTicks backoff_release_time_;
-
-  // If writing results to a file, |temp_file_writer_| will manage creation,
-  // writing, and destruction of that file.
-  scoped_ptr<TempFileWriter> temp_file_writer_;
-
-  // Where should responses be saved?
-  ResponseDestinationType response_destination_;
-
-  static base::LazyInstance<Registry> g_registry;
-
-  friend class URLFetcher;
-  DISALLOW_COPY_AND_ASSIGN(Core);
-};
-
-URLFetcher::Core::Registry::Registry() {}
-URLFetcher::Core::Registry::~Registry() {}
-
-void URLFetcher::Core::Registry::AddURLFetcherCore(Core* core) {
-  DCHECK(!ContainsKey(fetchers_, core));
-  fetchers_.insert(core);
-}
-
-void URLFetcher::Core::Registry::RemoveURLFetcherCore(Core* core) {
-  DCHECK(ContainsKey(fetchers_, core));
-  fetchers_.erase(core);
-}
-
-void URLFetcher::Core::Registry::CancelAll() {
-  while (!fetchers_.empty())
-    (*fetchers_.begin())->CancelURLRequest();
-}
-
-// static
-base::LazyInstance<URLFetcher::Core::Registry>
-    URLFetcher::Core::g_registry(base::LINKER_INITIALIZED);
-
-URLFetcher::Core::TempFileWriter::TempFileWriter(
-    URLFetcher::Core* core,
-    scoped_refptr<base::MessageLoopProxy> file_message_loop_proxy)
-    : core_(core),
-      error_code_(base::PLATFORM_FILE_OK),
-      callback_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)),
-      file_message_loop_proxy_(file_message_loop_proxy) {
-}
-
-URLFetcher::Core::TempFileWriter::~TempFileWriter() {
-  Destroy();
-}
-
-void URLFetcher::Core::TempFileWriter::CreateTempFile() {
-  CHECK(file_message_loop_proxy_.get());
-  base::FileUtilProxy::CreateTemporary(
-      file_message_loop_proxy_,
-      callback_factory_.NewCallback(
-          &URLFetcher::Core::TempFileWriter::DidCreateTempFile));
-}
-
-void URLFetcher::Core::TempFileWriter::DidCreateTempFile(
-    base::PlatformFileError error_code,
-    base::PassPlatformFile file_handle,
-    FilePath file_path) {
-  if (base::PLATFORM_FILE_OK != error_code) {
-    error_code_ = error_code;
-    core_->InformDelegateFetchIsComplete();
-    return;
-  }
-
-  temp_file_ = file_path;
-
-  // The file was opened with async writes enabled.   FileUtilProxy::Write()
-  // treats a write that returns IO_PENDING as an error, and does not inform
-  // the caller.  We need to close and reopen the file with asyncronus writes
-  // disabled.
-  // TODO(skerner): Make FileUtilProxy::Write() play nice with async IO.
-  base::FileUtilProxy::Close(
-      file_message_loop_proxy_,
-      file_handle.ReleaseValue(),
-      callback_factory_.NewCallback(
-          &URLFetcher::Core::TempFileWriter::DidCloseTempFile));
-}
-
-void URLFetcher::Core::TempFileWriter::DidCloseTempFile(
-    base::PlatformFileError error_code) {
-  if (base::PLATFORM_FILE_OK != error_code) {
-    error_code_ = error_code;
-    core_->InformDelegateFetchIsComplete();
-    return;
-  }
-
-  int file_flags =
-      base::PLATFORM_FILE_CREATE_ALWAYS |
-      base::PLATFORM_FILE_WRITE |
-      base::PLATFORM_FILE_TEMPORARY;
-
-  base::FileUtilProxy::CreateOrOpen(
-      file_message_loop_proxy_,
-      temp_file_,
-      file_flags,
-      callback_factory_.NewCallback(
-          &URLFetcher::Core::TempFileWriter::DidReopenTempFile));
-}
-
-void URLFetcher::Core::TempFileWriter::DidReopenTempFile(
-    base::PlatformFileError error_code,
-    base::PassPlatformFile file_handle,
-    bool created) {
-  if (base::PLATFORM_FILE_OK != error_code) {
-    error_code_ = error_code;
-    core_->InformDelegateFetchIsComplete();
-    return;
-  }
-
-  temp_file_handle_ = file_handle.ReleaseValue();
-  total_bytes_written_ = 0;
-
-  core_->io_message_loop_proxy_->PostTask(
-      FROM_HERE,
-      NewRunnableMethod(core_, &Core::StartURLRequestWhenAppropriate));
-}
-
-void URLFetcher::Core::TempFileWriter::WriteBuffer(int num_bytes) {
-  // Start writing to the temp file by setting the initial state
-  // of |pending_bytes_| and |buffer_offset_| to indicate that the
-  // entire buffer has not yet been written.
-  pending_bytes_ = num_bytes;
-  buffer_offset_ = 0;
-  ContinueWrite(base::PLATFORM_FILE_OK, 0);
-}
-
-void URLFetcher::Core::TempFileWriter::ContinueWrite(
-    base::PlatformFileError error_code,
-    int bytes_written) {
-  if (base::PLATFORM_FILE_OK != error_code) {
-    error_code_ = error_code;
-    core_->InformDelegateFetchIsComplete();
-    return;
-  }
-
-  total_bytes_written_ += bytes_written;
-  buffer_offset_ += bytes_written;
-  pending_bytes_ -= bytes_written;
-
-  if (pending_bytes_ > 0) {
-    base::FileUtilProxy::Write(
-        file_message_loop_proxy_,
-        temp_file_handle_,
-        total_bytes_written_,  // Append to the end
-        (core_->buffer_->data() + buffer_offset_),
-        pending_bytes_,
-        callback_factory_.NewCallback(
-            &URLFetcher::Core::TempFileWriter::ContinueWrite));
-  } else {
-    // Finished writing core_->buffer_ to the file. Read some more.
-    core_->ReadResponse();
-  }
-}
-
-void URLFetcher::Core::TempFileWriter::DisownTempFile() {
-  // Forget about any temp file by reseting the path.
-  if (!temp_file_.empty()) {
-    base::FileUtilProxy::Close(
-        file_message_loop_proxy_,
-        temp_file_handle_,
-        NULL);
-    temp_file_ = FilePath();
-  }
-}
-
-void URLFetcher::Core::TempFileWriter::Destroy() {
-  if (!temp_file_.empty()) {
-    base::FileUtilProxy::Close(
-        file_message_loop_proxy_,
-        temp_file_handle_,
-        NULL);
-
-    base::FileUtilProxy::Delete(
-        file_message_loop_proxy_,
-        temp_file_,
-        false,  // No need to recurse, as the path is to a file.
-        NULL);  // No callback.
-  }
-  temp_file_ = FilePath();
-}
-
-// static
-URLFetcher::Factory* URLFetcher::factory_ = NULL;
-
-void URLFetcher::Delegate::OnURLFetchComplete(
-    const URLFetcher* source,
-    const GURL& url,
-    const net::URLRequestStatus& status,
-    int response_code,
-    const net::ResponseCookies& cookies,
-    const std::string& data) {
-  NOTREACHED() << "If you don't implemnt this, the no-params version "
-               << "should also be implemented, in which case this "
-               << "method won't be called...";
-}
-
-// TODO(skerner): This default implementation will be removed, and the
-// method made pure virtual, once all users of URLFetcher are updated
-// to not expect response data as a string argument.  Once this is removed,
-// the method URLFetcher::GetResponseStringRef() can be removed as well.
-// crbug.com/83592 tracks this.
-void URLFetcher::Delegate::OnURLFetchComplete(const URLFetcher* source) {
-  // A delegate that did not override this method is using the old
-  // parameter list to OnURLFetchComplete(). If a user asked to save
-  // the response to a file, they must use the new parameter list,
-  // in which case we can not get here.
-  // To avoid updating all callers, thunk to the old prototype for now.
-  OnURLFetchComplete(source,
-                     source->url(),
-                     source->status(),
-                     source->response_code(),
-                     source->cookies(),
-                     source->GetResponseStringRef());
-}
-
-// static
-bool URLFetcher::g_interception_enabled = false;
-
-URLFetcher::URLFetcher(const GURL& url,
-                       RequestType request_type,
-                       Delegate* d)
-    : ALLOW_THIS_IN_INITIALIZER_LIST(
-      core_(new Core(this, url, request_type, d))),
-      automatically_retry_on_5xx_(true),
-      max_retries_(0) {
-}
-
-URLFetcher::~URLFetcher() {
-  core_->Stop();
-}
-
-// static
-URLFetcher* URLFetcher::Create(int id, const GURL& url,
-                               RequestType request_type, Delegate* d) {
-  return factory_ ? factory_->CreateURLFetcher(id, url, request_type, d) :
-                    new URLFetcher(url, request_type, d);
-}
-
-URLFetcher::Core::Core(URLFetcher* fetcher,
-                       const GURL& original_url,
-                       RequestType request_type,
-                       URLFetcher::Delegate* d)
-    : fetcher_(fetcher),
-      original_url_(original_url),
-      request_type_(request_type),
-      delegate_(d),
-      delegate_loop_proxy_(
-          base::MessageLoopProxy::CreateForCurrentThread()),
-      request_(NULL),
-      load_flags_(net::LOAD_NORMAL),
-      response_code_(URLFetcher::kInvalidHttpResponseCode),
-      buffer_(new net::IOBuffer(kBufferSize)),
-      is_chunked_upload_(false),
-      num_retries_(0),
-      was_cancelled_(false),
-      response_destination_(STRING) {
-}
-
-URLFetcher::Core::~Core() {
-  // |request_| should be NULL.  If not, it's unsafe to delete it here since we
-  // may not be on the IO thread.
-  DCHECK(!request_.get());
-}
-
-void URLFetcher::Core::Start() {
-  DCHECK(delegate_loop_proxy_);
-  CHECK(request_context_getter_) << "We need an URLRequestContext!";
-  io_message_loop_proxy_ = request_context_getter_->GetIOMessageLoopProxy();
-  CHECK(io_message_loop_proxy_.get()) << "We need an IO message loop proxy";
-
-  switch (response_destination_) {
-    case STRING:
-      io_message_loop_proxy_->PostTask(
-          FROM_HERE,
-          NewRunnableMethod(this, &Core::StartURLRequestWhenAppropriate));
-      break;
-
-    case TEMP_FILE:
-      CHECK(file_message_loop_proxy_.get())
-          << "Need to set the file message loop proxy.";
-      temp_file_writer_.reset(
-          new TempFileWriter(this, file_message_loop_proxy_));
-      // CreateTempFile() will invoke Core::StartURLRequestWhenAppropriate
-      // once the file is created.
-      temp_file_writer_->CreateTempFile();
-      break;
-
-    default:
-      NOTREACHED();
-  }
-}
-
-void URLFetcher::Core::Stop() {
-  DCHECK(delegate_loop_proxy_->BelongsToCurrentThread());
-  delegate_ = NULL;
-  fetcher_ = NULL;
-  if (io_message_loop_proxy_.get()) {
-    io_message_loop_proxy_->PostTask(
-        FROM_HERE, NewRunnableMethod(this, &Core::CancelURLRequest));
-  }
-}
-
-void URLFetcher::Core::ReceivedContentWasMalformed() {
-  DCHECK(delegate_loop_proxy_->BelongsToCurrentThread());
-  if (io_message_loop_proxy_.get()) {
-    io_message_loop_proxy_->PostTask(
-        FROM_HERE, NewRunnableMethod(this, &Core::NotifyMalformedContent));
-  }
-}
-
-void URLFetcher::Core::CancelAll() {
-  g_registry.Get().CancelAll();
-}
-
-void URLFetcher::Core::OnResponseStarted(net::URLRequest* request) {
-  DCHECK_EQ(request, request_.get());
-  DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
-  if (request_->status().is_success()) {
-    response_code_ = request_->GetResponseCode();
-    response_headers_ = request_->response_headers();
-    socket_address_ = request_->GetSocketAddress();
-    was_fetched_via_proxy_ = request_->was_fetched_via_proxy();
-  }
-
-  ReadResponse();
-}
-
-void URLFetcher::Core::CompleteAddingUploadDataChunk(
-    const std::string& content, bool is_last_chunk) {
-  DCHECK(is_chunked_upload_);
-  DCHECK(request_.get());
-  DCHECK(!content.empty());
-  request_->AppendChunkToUpload(content.data(),
-                                static_cast<int>(content.length()),
-                                is_last_chunk);
-}
-
-void URLFetcher::Core::AppendChunkToUpload(const std::string& content,
-                                           bool is_last_chunk) {
-  DCHECK(delegate_loop_proxy_);
-  CHECK(io_message_loop_proxy_.get());
-  io_message_loop_proxy_->PostTask(
-      FROM_HERE,
-      NewRunnableMethod(this, &Core::CompleteAddingUploadDataChunk, content,
-                        is_last_chunk));
-}
-
-// Return true if the write was done and reading may continue.
-// Return false if the write is pending, and the next read will
-// be done later.
-bool URLFetcher::Core::WriteBuffer(int num_bytes) {
-  bool write_complete = false;
-  switch (response_destination_) {
-    case STRING:
-      data_.append(buffer_->data(), num_bytes);
-      write_complete = true;
-      break;
-
-    case TEMP_FILE:
-      temp_file_writer_->WriteBuffer(num_bytes);
-      // WriteBuffer() sends a request the file thread.
-      // The write is not done yet.
-      write_complete = false;
-      break;
-
-    default:
-      NOTREACHED();
-  }
-  return write_complete;
-}
-
-void URLFetcher::Core::OnReadCompleted(net::URLRequest* request,
-                                       int bytes_read) {
-  DCHECK(request == request_);
-  DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
-
-  url_ = request->url();
-  url_throttler_entry_ =
-      net::URLRequestThrottlerManager::GetInstance()->RegisterRequestUrl(url_);
-
-  bool waiting_on_write = false;
-  do {
-    if (!request_->status().is_success() || bytes_read <= 0)
-      break;
-
-    if (!WriteBuffer(bytes_read)) {
-      // If WriteBuffer() returns false, we have a pending write to
-      // wait on before reading further.
-      waiting_on_write = true;
-      break;
-    }
-  } while (request_->Read(buffer_, kBufferSize, &bytes_read));
-
-  if (request_->status().is_success())
-    request_->GetResponseCookies(&cookies_);
-
-  // See comments re: HEAD requests in ReadResponse().
-  if ((!request_->status().is_io_pending() && !waiting_on_write) ||
-      (request_type_ == HEAD)) {
-    backoff_release_time_ = GetBackoffReleaseTime();
-
-    bool posted = delegate_loop_proxy_->PostTask(
-        FROM_HERE,
-        NewRunnableMethod(this,
-                          &Core::OnCompletedURLRequest,
-                          request_->status()));
-    // If the delegate message loop does not exist any more, then the delegate
-    // should be gone too.
-    DCHECK(posted || !delegate_);
-    ReleaseRequest();
-  }
-}
-
-void URLFetcher::Core::ReadResponse() {
-  // Some servers may treat HEAD requests as GET requests.  To free up the
-  // network connection as soon as possible, signal that the request has
-  // completed immediately, without trying to read any data back (all we care
-  // about is the response code and headers, which we already have).
-  int bytes_read = 0;
-  if (request_->status().is_success() && (request_type_ != HEAD))
-    request_->Read(buffer_, kBufferSize, &bytes_read);
-  OnReadCompleted(request_.get(), bytes_read);
-}
-
-void URLFetcher::Core::StartURLRequest() {
-  DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
-
-  if (was_cancelled_) {
-    // Since StartURLRequest() is posted as a *delayed* task, it may
-    // run after the URLFetcher was already stopped.
-    return;
-  }
-
-  CHECK(request_context_getter_);
-  DCHECK(!request_.get());
-
-  g_registry.Get().AddURLFetcherCore(this);
-  request_.reset(new net::URLRequest(original_url_, this));
-  int flags = request_->load_flags() | load_flags_;
-  if (!g_interception_enabled) {
-    flags = flags | net::LOAD_DISABLE_INTERCEPT;
-  }
-  if (is_chunked_upload_)
-    request_->EnableChunkedUpload();
-  request_->set_load_flags(flags);
-  request_->set_context(request_context_getter_->GetURLRequestContext());
-  request_->set_referrer(referrer_);
-
-  switch (request_type_) {
-    case GET:
-      break;
-
-    case POST:
-      DCHECK(!upload_content_.empty() || is_chunked_upload_);
-      DCHECK(!upload_content_type_.empty());
-
-      request_->set_method("POST");
-      extra_request_headers_.SetHeader(net::HttpRequestHeaders::kContentType,
-                                       upload_content_type_);
-      if (!upload_content_.empty()) {
-        request_->AppendBytesToUpload(
-            upload_content_.data(), static_cast<int>(upload_content_.length()));
-      }
-      break;
-
-    case HEAD:
-      request_->set_method("HEAD");
-      break;
-
-    default:
-      NOTREACHED();
-  }
-
-  if (!extra_request_headers_.IsEmpty())
-    request_->SetExtraRequestHeaders(extra_request_headers_);
-
-  // There might be data left over from a previous request attempt.
-  data_.clear();
-
-  // If we are writing the response to a file, the only caller
-  // of this function should have created it and not written yet.
-  CHECK(!temp_file_writer_.get() ||
-        temp_file_writer_->total_bytes_written() == 0);
-
-  request_->Start();
-}
-
-void URLFetcher::Core::StartURLRequestWhenAppropriate() {
-  DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
-
-  if (was_cancelled_)
-    return;
-
-  if (original_url_throttler_entry_ == NULL) {
-    original_url_throttler_entry_ =
-        net::URLRequestThrottlerManager::GetInstance()->RegisterRequestUrl(
-            original_url_);
-  }
-
-  int64 delay = original_url_throttler_entry_->ReserveSendingTimeForNextRequest(
-      GetBackoffReleaseTime());
-  if (delay == 0) {
-    StartURLRequest();
-  } else {
-    MessageLoop::current()->PostDelayedTask(
-        FROM_HERE,
-        NewRunnableMethod(this, &Core::StartURLRequest),
-        delay);
-  }
-}
-
-void URLFetcher::Core::CancelURLRequest() {
-  DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
-
-  if (request_.get()) {
-    request_->Cancel();
-    ReleaseRequest();
-  }
-  // Release the reference to the request context. There could be multiple
-  // references to URLFetcher::Core at this point so it may take a while to
-  // delete the object, but we cannot delay the destruction of the request
-  // context.
-  request_context_getter_ = NULL;
-  was_cancelled_ = true;
-  temp_file_writer_.reset();
-}
-
-void URLFetcher::Core::OnCompletedURLRequest(
-    const net::URLRequestStatus& status) {
-  DCHECK(delegate_loop_proxy_->BelongsToCurrentThread());
-
-  // Save the status so that delegates can read it.
-  status_ = status;
-
-  // Checks the response from server.
-  if (response_code_ >= 500 ||
-      status.os_error() == net::ERR_TEMPORARILY_THROTTLED) {
-    // When encountering a server error, we will send the request again
-    // after backoff time.
-    ++num_retries_;
-    // Restarts the request if we still need to notify the delegate.
-    if (delegate_) {
-      // Note that backoff_delay_ may be 0 because (a) the URLRequestThrottler
-      // code does not necessarily back off on the first error, and (b) it
-      // only backs off on some of the 5xx status codes.
-      fetcher_->backoff_delay_ = backoff_release_time_ - base::TimeTicks::Now();
-      if (fetcher_->backoff_delay_ < base::TimeDelta())
-        fetcher_->backoff_delay_ = base::TimeDelta();
-
-      if (fetcher_->automatically_retry_on_5xx_ &&
-          num_retries_ <= fetcher_->max_retries()) {
-        io_message_loop_proxy_->PostTask(
-            FROM_HERE,
-            NewRunnableMethod(this, &Core::StartURLRequestWhenAppropriate));
-      } else {
-        InformDelegateFetchIsComplete();
-      }
-    }
-  } else {
-    if (delegate_) {
-      fetcher_->backoff_delay_ = base::TimeDelta();
-      InformDelegateFetchIsComplete();
-    }
-  }
-}
-
-void URLFetcher::Core::InformDelegateFetchIsComplete() {
-  delegate_->OnURLFetchComplete(fetcher_);
-}
-
-void URLFetcher::Core::NotifyMalformedContent() {
-  DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
-  if (url_throttler_entry_ != NULL) {
-    int status_code = response_code_;
-    if (status_code == kInvalidHttpResponseCode) {
-      // The status code will generally be known by the time clients
-      // call the |ReceivedContentWasMalformed()| function (which ends up
-      // calling the current function) but if it's not, we need to assume
-      // the response was successful so that the total failure count
-      // used to calculate exponential back-off goes up.
-      status_code = 200;
-    }
-    url_throttler_entry_->ReceivedContentWasMalformed(status_code);
-  }
-}
-
-void URLFetcher::Core::ReleaseRequest() {
-  request_.reset();
-  g_registry.Get().RemoveURLFetcherCore(this);
-}
-
-base::TimeTicks URLFetcher::Core::GetBackoffReleaseTime() {
-  DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
-  DCHECK(original_url_throttler_entry_ != NULL);
-
-  base::TimeTicks original_url_backoff =
-      original_url_throttler_entry_->GetExponentialBackoffReleaseTime();
-  base::TimeTicks destination_url_backoff;
-  if (url_throttler_entry_ != NULL &&
-      original_url_throttler_entry_ != url_throttler_entry_) {
-    destination_url_backoff =
-        url_throttler_entry_->GetExponentialBackoffReleaseTime();
-  }
-
-  return original_url_backoff > destination_url_backoff ?
-      original_url_backoff : destination_url_backoff;
-}
-
-void URLFetcher::set_upload_data(const std::string& upload_content_type,
-                                 const std::string& upload_content) {
-  DCHECK(!core_->is_chunked_upload_);
-  core_->upload_content_type_ = upload_content_type;
-  core_->upload_content_ = upload_content;
-}
-
-void URLFetcher::set_chunked_upload(const std::string& content_type) {
-  DCHECK(core_->is_chunked_upload_ ||
-         (core_->upload_content_type_.empty() &&
-          core_->upload_content_.empty()));
-  core_->upload_content_type_ = content_type;
-  core_->upload_content_.clear();
-  core_->is_chunked_upload_ = true;
-}
-
-void URLFetcher::AppendChunkToUpload(const std::string& data,
-                                     bool is_last_chunk) {
-  DCHECK(data.length());
-  core_->AppendChunkToUpload(data, is_last_chunk);
-}
-
-const std::string& URLFetcher::upload_data() const {
-  return core_->upload_content_;
-}
-
-void URLFetcher::set_referrer(const std::string& referrer) {
-  core_->referrer_ = referrer;
-}
-
-void URLFetcher::set_load_flags(int load_flags) {
-  core_->load_flags_ = load_flags;
-}
-
-int URLFetcher::load_flags() const {
-  return core_->load_flags_;
-}
-
-void URLFetcher::set_extra_request_headers(
-    const std::string& extra_request_headers) {
-  core_->extra_request_headers_.Clear();
-  core_->extra_request_headers_.AddHeadersFromString(extra_request_headers);
-}
-
-void URLFetcher::set_request_context(
-    net::URLRequestContextGetter* request_context_getter) {
-  core_->request_context_getter_ = request_context_getter;
-}
-
-void URLFetcher::set_automatically_retry_on_5xx(bool retry) {
-  automatically_retry_on_5xx_ = retry;
-}
-
-void URLFetcher::SaveResponseToTemporaryFile(
-    scoped_refptr<base::MessageLoopProxy> file_message_loop_proxy) {
-  core_->file_message_loop_proxy_ = file_message_loop_proxy;
-  core_->response_destination_ = TEMP_FILE;
-}
-
-net::HttpResponseHeaders* URLFetcher::response_headers() const {
-  return core_->response_headers_;
-}
-
-// TODO(panayiotis): socket_address_ is written in the IO thread,
-// if this is accessed in the UI thread, this could result in a race.
-// Same for response_headers_ above and was_fetched_via_proxy_ below.
-net::HostPortPair URLFetcher::socket_address() const {
-  return core_->socket_address_;
-}
-
-bool URLFetcher::was_fetched_via_proxy() const {
-  return core_->was_fetched_via_proxy_;
-}
-
-void URLFetcher::Start() {
-  core_->Start();
-}
-
-const GURL& URLFetcher::url() const {
-  return core_->url_;
-}
-
-const net::URLRequestStatus& URLFetcher::status() const {
-  return core_->status_;
-}
-
-int URLFetcher::response_code() const {
-  return core_->response_code_;
-}
-
-const net::ResponseCookies& URLFetcher::cookies() const {
-  return core_->cookies_;
-}
-
-bool URLFetcher::FileErrorOccurred(
-    base::PlatformFileError* out_error_code) const {
-
-  // Can't have a file error if no file is being created or written to.
-  if (!core_->temp_file_writer_.get()) {
-    return false;
-  }
-
-  base::PlatformFileError error_code = core_->temp_file_writer_->error_code();
-  if (error_code == base::PLATFORM_FILE_OK)
-    return false;
-
-  *out_error_code = error_code;
-  return true;
-}
-
-void URLFetcher::ReceivedContentWasMalformed() {
-  core_->ReceivedContentWasMalformed();
-}
-
-bool URLFetcher::GetResponseAsString(std::string* out_response_string) const {
-  if (core_->response_destination_ != STRING)
-    return false;
-
-  *out_response_string = core_->data_;
-  return true;
-}
-
-const std::string& URLFetcher::GetResponseStringRef() const {
-  CHECK(core_->response_destination_ == STRING);
-  return core_->data_;
-}
-
-void URLFetcher::SetResponseDestinationForTesting(
-    ResponseDestinationType value) {
-  core_->response_destination_ = value;
-}
-
-URLFetcher::ResponseDestinationType
-URLFetcher::GetResponseDestinationForTesting() const {
-  return core_->response_destination_;
-}
-
-bool URLFetcher::GetResponseAsFilePath(bool take_ownership,
-                                       FilePath* out_response_path) const {
-  if (core_->response_destination_ != TEMP_FILE ||
-      !core_->temp_file_writer_.get())
-    return false;
-
-  *out_response_path = core_->temp_file_writer_->temp_file();
-
-  if (take_ownership)
-    core_->temp_file_writer_->DisownTempFile();
-
-  return true;
-}
-
-// static
-void URLFetcher::CancelAll() {
-  Core::CancelAll();
-}
-
-// static
-int URLFetcher::GetNumFetcherCores() {
-  return Core::g_registry.Get().size();
-}
-
-URLFetcher::Delegate* URLFetcher::delegate() const {
-  return core_->delegate();
-}