WIP - Refactor programmatic downloads

content/browser/download/download_resource_handler.cc

Index: content/browser/download/download_resource_handler.cc
diff --git a/content/browser/download/download_resource_handler.cc b/content/browser/download/download_resource_handler.cc
index ed4edff67fe26cde16773044a6c1e4bc97d8545b..5b1e43703a88c34b1a877445046faa3aab6787f2 100644
--- a/content/browser/download/download_resource_handler.cc
+++ b/content/browser/download/download_resource_handler.cc
@@ -8,6 +8,7 @@
 
 #include "base/bind.h"
 #include "base/logging.h"
+#include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/stats_counters.h"
@@ -20,6 +21,9 @@
 #include "content/browser/download/download_stats.h"
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 #include "content/browser/loader/resource_request_info_impl.h"
+#include "content/browser/renderer_host/render_view_host_impl.h"
+#include "content/browser/web_contents/web_contents_impl.h"
+#include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/download_interrupt_reasons.h"
 #include "content/public/browser/download_item.h"
@@ -34,62 +38,129 @@
 namespace content {
 namespace {
 
-void CallStartedCBOnUIThread(
-    const DownloadUrlParameters::OnStartedCallback& started_cb,
-    DownloadItem* item,
-    net::Error error) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+class DownloadResourceHandlerRequestHandle : public DownloadRequestHandle {
+ public:
+  virtual ~DownloadResourceHandlerRequestHandle();
+
+  DownloadResourceHandlerRequestHandle(
+      const base::WeakPtr<DownloadResourceHandler>& handler,
+      int child_id,
+      int render_view_id,
+      int request_id);
+
+  // DownloadRequestHandle.
+  virtual void Start(const RequestStartedCallback& started_callback) OVERRIDE;
+  virtual void PauseRequest() const OVERRIDE;
+  virtual void ResumeRequest() const OVERRIDE;
+  virtual void CancelRequest() const OVERRIDE;
+  virtual std::string DebugString() const OVERRIDE;
+
+ private:
+  base::WeakPtr<DownloadResourceHandler> handler_;
+
+  // The ID of the child process that started the download.
+  int child_id_;
+
+  // The ID of the render view that started the download.
+  int render_view_id_;
+
+  // The ID associated with the request used for the download.
+  int request_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(DownloadResourceHandlerRequestHandle);
+};
+
+DownloadResourceHandlerRequestHandle::~DownloadResourceHandlerRequestHandle() {}
+
+DownloadResourceHandlerRequestHandle::DownloadResourceHandlerRequestHandle(
+    const base::WeakPtr<DownloadResourceHandler>& handler,
+    int child_id,
+    int render_view_id,
+    int request_id)
+    : handler_(handler),
+      child_id_(child_id),
+      render_view_id_(render_view_id),
+      request_id_(request_id) {
+  DCHECK(handler_.get());
+}
 
-  if (started_cb.is_null())
-    return;
-  started_cb.Run(item, error);
+void DownloadResourceHandlerRequestHandle::Start(
+    const RequestStartedCallback& started_callback) {
+  // Start() shouldn't be getting called this request handle since
+  // DownloadManager::StartDownloadWithActiveRequest() assumes that the request
+  // is already in progress.
+  NOTREACHED();
+}
+
+void DownloadResourceHandlerRequestHandle::PauseRequest() const {
+  BrowserThread::PostTask(
+      BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&DownloadResourceHandler::PauseRequest, handler_));
+}
+
+void DownloadResourceHandlerRequestHandle::ResumeRequest() const {
+  BrowserThread::PostTask(
+      BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&DownloadResourceHandler::ResumeRequest, handler_));
+}
+
+void DownloadResourceHandlerRequestHandle::CancelRequest() const {
+  BrowserThread::PostTask(
+      BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&DownloadResourceHandler::CancelRequest, handler_));
+}
+
+std::string DownloadResourceHandlerRequestHandle::DebugString() const {
+  return base::StringPrintf(
+      "{"
+      " child_id = %d"
+      " render_view_id = %d"
+      " request_id = %d"
+      "}",
+      child_id_,
+      render_view_id_,
+      request_id_);
 }
 
 // Static function in order to prevent any accidental accesses to
 // DownloadResourceHandler members from the UI thread.
-static void StartOnUIThread(
-    scoped_ptr<DownloadCreateInfo> info,
-    scoped_ptr<ByteStreamReader> stream,
-    const DownloadUrlParameters::OnStartedCallback& started_cb) {
+static void StartOnUIThread(int child_id,
+                            int render_view_id,
+                            scoped_ptr<DownloadRequestHandle> handle,
+                            scoped_ptr<DownloadCreateInfo> info) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  DownloadManager* download_manager = info->request_handle.GetDownloadManager();
-  if (!download_manager) {
-    // NULL in unittests or if the page closed right after starting the
-    // download.
-    if (!started_cb.is_null())
-      started_cb.Run(NULL, net::ERR_ACCESS_DENIED);
+  RenderViewHostImpl* rvh =
+      RenderViewHostImpl::FromID(child_id, render_view_id);
+  if (rvh == NULL)
     return;
-  }
-
-  download_manager->StartDownload(info.Pass(), stream.Pass(), started_cb);
+  RenderProcessHost* rph = rvh->GetProcess();
+  if (rph == NULL)
+    return;
+  BrowserContext* context = rph->GetBrowserContext();
+  if (context == NULL)
+    return;
+  DownloadManager* download_manager =
+      BrowserContext::GetDownloadManager(context);
+  if (download_manager)
+    download_manager->StartDownloadWithActiveRequest(handle.Pass(),
+                                                     info.Pass());
 }
 
 }  // namespace
 
-const int DownloadResourceHandler::kDownloadByteStreamSize = 100 * 1024;
-
 DownloadResourceHandler::DownloadResourceHandler(
-    uint32 id,
-    net::URLRequest* request,
-    const DownloadUrlParameters::OnStartedCallback& started_cb,
-    scoped_ptr<DownloadSaveInfo> save_info)
-    : download_id_(id),
-      render_view_id_(0),               // Actually initialized below.
-      content_length_(0),
-      request_(request),
-      started_cb_(started_cb),
-      save_info_(save_info.Pass()),
-      last_buffer_size_(0),
-      bytes_read_(0),
-      pause_count_(0),
-      was_deferred_(false),
+    net::URLRequest* request)
+    : request_model_(request, make_scoped_ptr(new DownloadSaveInfo())),
+      render_view_id_(0),  // Actually initialized below.
+      did_defer_request_(false),
       on_response_started_called_(false) {
   ResourceRequestInfoImpl* info(ResourceRequestInfoImpl::ForRequest(request));
   global_id_ = info->GetGlobalRequestID();
   render_view_id_ = info->GetRouteID();
-
-  RecordDownloadCount(UNTHROTTLED_COUNT);
 }
 
 bool DownloadResourceHandler::OnUploadProgress(int request_id,
@@ -103,9 +174,7 @@ bool DownloadResourceHandler::OnRequestRedirected(
     const GURL& url,
     ResourceResponse* response,
     bool* defer) {
-  // We treat a download as a main frame load, and thus update the policy URL
-  // on redirects.
-  request_->set_first_party_for_cookies(url);
+  request_model_.OnRequestRedirected(url);
   return true;
 }
 
@@ -119,115 +188,35 @@ bool DownloadResourceHandler::OnResponseStarted(
   DCHECK(!on_response_started_called_);
   on_response_started_called_ = true;
 
-  VLOG(20) << __FUNCTION__ << "()" << DebugString()
-           << " request_id = " << request_id;
-  download_start_time_ = base::TimeTicks::Now();
-
-  // If it's a download, we don't want to poison the cache with it.
-  request_->StopCaching();
-
-  // Lower priority as well, so downloads don't contend for resources
-  // with main frames.
-  request_->SetPriority(net::IDLE);
-
-  std::string content_disposition;
-  request_->GetResponseHeaderByName("content-disposition",
-                                    &content_disposition);
-  SetContentDisposition(content_disposition);
-  SetContentLength(response->head.content_length);
+  DVLOG(20) << __FUNCTION__ << "()" << DebugString()
+            << " request_id = " << request_id;
 
   const ResourceRequestInfoImpl* request_info =
-      ResourceRequestInfoImpl::ForRequest(request_);
-
-  // Deleted in DownloadManager.
-  scoped_ptr<DownloadCreateInfo> info(new DownloadCreateInfo(
-      base::Time::Now(), content_length_,
-      request_->net_log(), request_info->HasUserGesture(),
-      request_info->GetPageTransition()));
-
-  // Create the ByteStream for sending data to the download sink.
-  scoped_ptr<ByteStreamReader> stream_reader;
-  CreateByteStream(
-      base::MessageLoopProxy::current(),
-      BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE),
-      kDownloadByteStreamSize, &stream_writer_, &stream_reader);
-  stream_writer_->RegisterCallback(
-      base::Bind(&DownloadResourceHandler::ResumeRequest, AsWeakPtr()));
-
-  info->download_id = download_id_;
-  info->url_chain = request_->url_chain();
-  info->referrer_url = GURL(request_->referrer());
-  info->start_time = base::Time::Now();
-  info->total_bytes = content_length_;
-  info->has_user_gesture = request_info->HasUserGesture();
-  info->content_disposition = content_disposition_;
-  info->mime_type = response->head.mime_type;
-  info->remote_address = request_->GetSocketAddress().host();
-  RecordDownloadMimeType(info->mime_type);
-  RecordDownloadContentDisposition(info->content_disposition);
-
-  info->request_handle =
-      DownloadRequestHandle(AsWeakPtr(), global_id_.child_id,
-                            render_view_id_, global_id_.request_id);
-
-  // Get the last modified time and etag.
-  const net::HttpResponseHeaders* headers = request_->response_headers();
-  if (headers) {
-    std::string last_modified_hdr;
-    if (headers->EnumerateHeader(NULL, "Last-Modified", &last_modified_hdr))
-      info->last_modified = last_modified_hdr;
-    if (headers->EnumerateHeader(NULL, "ETag", &etag_))
-      info->etag = etag_;
-
-    int status = headers->response_code();
-    if (2 == status / 100  && status != net::HTTP_PARTIAL_CONTENT) {
-      // Success & not range response; if we asked for a range, we didn't
-      // get it--reset the file pointers to reflect that.
-      save_info_->offset = 0;
-      save_info_->hash_state = "";
-    }
-  }
-
-  std::string content_type_header;
-  if (!response->head.headers.get() ||
-      !response->head.headers->GetMimeType(&content_type_header))
-    content_type_header = "";
-  info->original_mime_type = content_type_header;
-
-  if (!response->head.headers.get() ||
-      !response->head.headers->EnumerateHeader(
-          NULL, "Accept-Ranges", &accept_ranges_)) {
-    accept_ranges_ = "";
-  }
-
-  info->save_info = save_info_.Pass();
-
-  BrowserThread::PostTask(
-      BrowserThread::UI, FROM_HERE,
-      base::Bind(&StartOnUIThread,
-                 base::Passed(&info),
-                 base::Passed(&stream_reader),
-                 // Pass to StartOnUIThread so that variable
-                 // access is always on IO thread but function
-                 // is called on UI thread.
-                 started_cb_));
-  // Guaranteed to be called in StartOnUIThread
-  started_cb_.Reset();
-
+      ResourceRequestInfoImpl::ForRequest(request_model_.request());
+
+  DownloadRequestModel::ResumeRequestCallback resume_callback =
+      base::Bind(&DownloadResourceHandler::ResumeRequest, AsWeakPtr());
+  scoped_ptr<DownloadCreateInfo> create_info =
+      request_model_.OnResponseStarted(response->head.mime_type,
+                                       request_info->HasUserGesture(),
+                                       request_info->GetPageTransition(),
+                                       resume_callback);
+
+  scoped_ptr<DownloadRequestHandle> request_handle(
+      new DownloadResourceHandlerRequestHandle(AsWeakPtr(),
+                                               global_id_.child_id,
+                                               render_view_id_,
+                                               global_id_.request_id));
+  BrowserThread::PostTask(BrowserThread::UI,
+                          FROM_HERE,
+                          base::Bind(&StartOnUIThread,
+                                     global_id_.child_id,
+                                     render_view_id_,
+                                     base::Passed(&request_handle),
+                                     base::Passed(&create_info)));
   return true;
 }
 
-void DownloadResourceHandler::CallStartedCB(
-    DownloadItem* item, net::Error error) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  if (started_cb_.is_null())
-    return;
-  BrowserThread::PostTask(
-      BrowserThread::UI, FROM_HERE,
-      base::Bind(&CallStartedCBOnUIThread, started_cb_, item, error));
-  started_cb_.Reset();
-}
-
 bool DownloadResourceHandler::OnWillStart(int request_id,
                                           const GURL& url,
                                           bool* defer) {
@@ -239,13 +228,7 @@ bool DownloadResourceHandler::OnWillStart(int request_id,
 bool DownloadResourceHandler::OnWillRead(int request_id, net::IOBuffer** buf,
                                          int* buf_size, int min_size) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DCHECK(buf && buf_size);
-  DCHECK(!read_buffer_.get());
-
-  *buf_size = min_size < 0 ? kReadBufSize : min_size;
-  last_buffer_size_ = *buf_size;
-  read_buffer_ = new net::IOBuffer(*buf_size);
-  *buf = read_buffer_.get();
+  request_model_.OnWillRead(buf, buf_size, min_size);
   return true;
 }
 
@@ -253,40 +236,10 @@ bool DownloadResourceHandler::OnWillRead(int request_id, net::IOBuffer** buf,
 bool DownloadResourceHandler::OnReadCompleted(int request_id, int bytes_read,
                                               bool* defer) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DCHECK(read_buffer_.get());
-
-  base::TimeTicks now(base::TimeTicks::Now());
-  if (!last_read_time_.is_null()) {
-    double seconds_since_last_read = (now - last_read_time_).InSecondsF();
-    if (now == last_read_time_)
-      // Use 1/10 ms as a "very small number" so that we avoid
-      // divide-by-zero error and still record a very high potential bandwidth.
-      seconds_since_last_read = 0.00001;
-
-    double actual_bandwidth = (bytes_read)/seconds_since_last_read;
-    double potential_bandwidth = last_buffer_size_/seconds_since_last_read;
-    RecordBandwidth(actual_bandwidth, potential_bandwidth);
-  }
-  last_read_time_ = now;
-
-  if (!bytes_read)
-    return true;
-  bytes_read_ += bytes_read;
-  DCHECK(read_buffer_.get());
-
-  // Take the data ship it down the stream.  If the stream is full, pause the
-  // request; the stream callback will resume it.
-  if (!stream_writer_->Write(read_buffer_, bytes_read)) {
-    PauseRequest();
-    *defer = was_deferred_ = true;
-    last_stream_pause_time_ = now;
-  }
-
-  read_buffer_ = NULL;  // Drop our reference.
-
-  if (pause_count_ > 0)
-    *defer = was_deferred_ = true;
-
+  DownloadRequestModel::ReadState read_state =
+      request_model_.OnReadCompleted(bytes_read);
+  if (read_state == DownloadRequestModel::WAIT_FOR_RESUME)
+    *defer = did_defer_request_ = true;
   return true;
 }
 
@@ -295,108 +248,11 @@ bool DownloadResourceHandler::OnResponseCompleted(
     const net::URLRequestStatus& status,
     const std::string& security_info) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  int response_code = status.is_success() ? request_->GetResponseCode() : 0;
-  VLOG(20) << __FUNCTION__ << "()" << DebugString()
-           << " request_id = " << request_id
-           << " status.status() = " << status.status()
-           << " status.error() = " << status.error()
-           << " response_code = " << response_code;
-
-  net::Error error_code = net::OK;
-  if (status.status() == net::URLRequestStatus::FAILED ||
-      // Note cancels as failures too.
-      status.status() == net::URLRequestStatus::CANCELED) {
-    error_code = static_cast<net::Error>(status.error());  // Normal case.
-    // Make sure that at least the fact of failure comes through.
-    if (error_code == net::OK)
-      error_code = net::ERR_FAILED;
-  }
-
-  // ERR_CONTENT_LENGTH_MISMATCH and ERR_INCOMPLETE_CHUNKED_ENCODING are
-  // allowed since a number of servers in the wild close the connection too
-  // early by mistake. Other browsers - IE9, Firefox 11.0, and Safari 5.1.4 -
-  // treat downloads as complete in both cases, so we follow their lead.
-  if (error_code == net::ERR_CONTENT_LENGTH_MISMATCH ||
-      error_code == net::ERR_INCOMPLETE_CHUNKED_ENCODING) {
-    error_code = net::OK;
-  }
-  DownloadInterruptReason reason =
-      ConvertNetErrorToInterruptReason(
-        error_code, DOWNLOAD_INTERRUPT_FROM_NETWORK);
-
-  if (status.status() == net::URLRequestStatus::CANCELED &&
-      status.error() == net::ERR_ABORTED) {
-    // CANCELED + ERR_ABORTED == something outside of the network
-    // stack cancelled the request.  There aren't that many things that
-    // could do this to a download request (whose lifetime is separated from
-    // the tab from which it came).  We map this to USER_CANCELLED as the
-    // case we know about (system suspend because of laptop close) corresponds
-    // to a user action.
-    // TODO(ahendrickson) -- Find a better set of codes to use here, as
-    // CANCELED/ERR_ABORTED can occur for reasons other than user cancel.
-    reason = DOWNLOAD_INTERRUPT_REASON_USER_CANCELED;
-  }
-
-  if (status.is_success() &&
-      reason == DOWNLOAD_INTERRUPT_REASON_NONE &&
-      request_->response_headers()) {
-    // Handle server's response codes.
-    switch(response_code) {
-      case -1:                          // Non-HTTP request.
-      case net::HTTP_OK:
-      case net::HTTP_CREATED:
-      case net::HTTP_ACCEPTED:
-      case net::HTTP_NON_AUTHORITATIVE_INFORMATION:
-      case net::HTTP_RESET_CONTENT:
-      case net::HTTP_PARTIAL_CONTENT:
-        // Expected successful codes.
-        break;
-      case net::HTTP_NO_CONTENT:
-      case net::HTTP_NOT_FOUND:
-        reason = DOWNLOAD_INTERRUPT_REASON_SERVER_BAD_CONTENT;
-        break;
-      case net::HTTP_PRECONDITION_FAILED:
-        // Failed our 'If-Unmodified-Since' or 'If-Match'; see
-        // download_manager_impl.cc BeginDownload()
-        reason = DOWNLOAD_INTERRUPT_REASON_SERVER_PRECONDITION;
-        break;
-      case net::HTTP_REQUESTED_RANGE_NOT_SATISFIABLE:
-        // Retry by downloading from the start automatically:
-        // If we haven't received data when we get this error, we won't.
-        reason = DOWNLOAD_INTERRUPT_REASON_SERVER_NO_RANGE;
-        break;
-      default:    // All other errors.
-        // Redirection and informational codes should have been handled earlier
-        // in the stack.
-        DCHECK_NE(3, response_code / 100);
-        DCHECK_NE(1, response_code / 100);
-        reason = DOWNLOAD_INTERRUPT_REASON_SERVER_FAILED;
-        break;
-    }
-  }
-
-  RecordAcceptsRanges(accept_ranges_, bytes_read_, etag_);
-  RecordNetworkBlockage(
-      base::TimeTicks::Now() - download_start_time_, total_pause_time_);
-
-  CallStartedCB(NULL, error_code);
-
-  // Send the info down the stream.  Conditional is in case we get
-  // OnResponseCompleted without OnResponseStarted.
-  if (stream_writer_)
-    stream_writer_->Close(reason);
-
-  // If the error mapped to something unknown, record it so that
-  // we can drill down.
-  if (reason == DOWNLOAD_INTERRUPT_REASON_NETWORK_FAILED) {
-    UMA_HISTOGRAM_CUSTOM_ENUMERATION("Download.MapErrorNetworkFailed",
-                                     std::abs(status.error()),
-                                     net::GetAllErrorCodesForUma());
-  }
-
-  stream_writer_.reset();  // We no longer need the stream.
-  read_buffer_ = NULL;
-
+  DVLOG(20) << __FUNCTION__ << "()" << DebugString()
+            << " request_id = " << request_id
+            << " status.status() = " << status.status()
+            << " status.error() = " << status.error();
+  request_model_.OnResponseCompleted();
   return true;
 }
 
@@ -406,46 +262,18 @@ void DownloadResourceHandler::OnDataDownloaded(
   NOTREACHED();
 }
 
-// If the content-length header is not present (or contains something other
-// than numbers), the incoming content_length is -1 (unknown size).
-// Set the content length to 0 to indicate unknown size to DownloadManager.
-void DownloadResourceHandler::SetContentLength(const int64& content_length) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  content_length_ = 0;
-  if (content_length > 0)
-    content_length_ = content_length;
-}
-
-void DownloadResourceHandler::SetContentDisposition(
-    const std::string& content_disposition) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  content_disposition_ = content_disposition;
-}
-
 void DownloadResourceHandler::PauseRequest() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-
-  ++pause_count_;
+  request_model_.OnPauseRequest();
 }
 
 void DownloadResourceHandler::ResumeRequest() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DCHECK_LT(0, pause_count_);
-
-  --pause_count_;
-
-  if (!was_deferred_)
-    return;
-  if (pause_count_ > 0)
-    return;
-
-  was_deferred_ = false;
-  if (!last_stream_pause_time_.is_null()) {
-    total_pause_time_ += (base::TimeTicks::Now() - last_stream_pause_time_);
-    last_stream_pause_time_ = base::TimeTicks();
+  if (request_model_.OnResumeRequest() == DownloadRequestModel::READY_TO_READ &&
+      did_defer_request_) {
+    did_defer_request_ = false;
+    controller()->Resume();
   }
-
-  controller()->Resume();
 }
 
 void DownloadResourceHandler::CancelRequest() {
@@ -458,36 +286,23 @@ void DownloadResourceHandler::CancelRequest() {
 }
 
 std::string DownloadResourceHandler::DebugString() const {
-  return base::StringPrintf("{"
-                            " url_ = " "\"%s\""
-                            " global_id_ = {"
-                            " child_id = " "%d"
-                            " request_id = " "%d"
-                            " }"
-                            " render_view_id_ = " "%d"
-                            " }",
-                            request_ ?
-                                request_->url().spec().c_str() :
-                                "<NULL request>",
-                            global_id_.child_id,
-                            global_id_.request_id,
-                            render_view_id_);
+  return base::StringPrintf(
+      "{"
+      " request = %s"
+      " global_id_ = {"
+      "  child_id = %d"
+      "  request_id = %d"
+      " }"
+      " render_view_id_ = %d"
+      " }",
+      request_model_.DebugString().c_str(),
+      global_id_.child_id,
+      global_id_.request_id,
+      render_view_id_);
 }
 
 DownloadResourceHandler::~DownloadResourceHandler() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-
-  // This won't do anything if the callback was called before.
-  // If it goes through, it will likely be because OnWillStart() returned
-  // false somewhere in the chain of resource handlers.
-  CallStartedCB(NULL, net::ERR_ACCESS_DENIED);
-
-  // Remove output stream callback if a stream exists.
-  if (stream_writer_)
-    stream_writer_->RegisterCallback(base::Closure());
-
-  UMA_HISTOGRAM_TIMES("SB2.DownloadDuration",
-                      base::TimeTicks::Now() - download_start_time_);
 }
 
 }  // namespace content