Switch the TCP reads on Windows to use non-blocking/non-async I/O.

net/url_request/url_request_http_job.cc

 // 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.
 
 #include "net/url_request/url_request_http_job.h"
 
 #include "base/base_switches.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
@@ skipping 1270 matching lines @@
     NOTREACHED()
         << "The same transaction shouldn't start twice without new timing.";
     return;
   }
 
   base::TimeDelta to_start = base::Time::Now() - request_creation_time_;
   request_creation_time_ = base::Time();
 
   UMA_HISTOGRAM_MEDIUM_TIMES("Net.HttpTimeToFirstByte", to_start);
 
+  static const bool use_overlapped_read_histogram =
+      base::FieldTrialList::TrialExists("OverlappedReadImpact");
+  if (use_overlapped_read_histogram) {
+    UMA_HISTOGRAM_MEDIUM_TIMES(
+        base::FieldTrial::MakeName("Net.HttpTimeToFirstByte",
+                                   "OverlappedReadImpact"),
+        to_start);
+  }
+
   static const bool use_warm_socket_impact_histogram =
       base::FieldTrialList::TrialExists("WarmSocketImpact");
   if (use_warm_socket_impact_histogram) {
     UMA_HISTOGRAM_MEDIUM_TIMES(
         base::FieldTrial::MakeName("Net.HttpTimeToFirstByte",
                                    "WarmSocketImpact"),
         to_start);
   }
 
   static const bool use_prefetch_histogram =
@@ skipping 173 matching lines @@
   }
 
   if (response_info_) {
     if (response_info_->was_cached) {
       UMA_HISTOGRAM_TIMES("Net.HttpJob.TotalTimeCached", total_time);
     } else  {
       UMA_HISTOGRAM_TIMES("Net.HttpJob.TotalTimeNotCached", total_time);
     }
   }
 
+  static const bool use_overlapped_read_histogram =
+      base::FieldTrialList::TrialExists("OverlappedReadImpact");
+  if (use_overlapped_read_histogram) {
+    UMA_HISTOGRAM_TIMES(
+        base::FieldTrial::MakeName("Net.HttpJob.TotalTime",
+                                   "OverlappedReadImpact"),
+        total_time);
+
+    if (reason == FINISHED) {
+      UMA_HISTOGRAM_TIMES(
+          base::FieldTrial::MakeName("Net.HttpJob.TotalTimeSuccess",
+                                     "OverlappedReadImpact"),
+          total_time);
+    } else {
+      UMA_HISTOGRAM_TIMES(
+          base::FieldTrial::MakeName("Net.HttpJob.TotalTimeCancel",
+                                     "OverlappedReadImpact"),
+          total_time);
+    }
+
+    if (response_info_) {
+      if (response_info_->was_cached) {
+        UMA_HISTOGRAM_TIMES(
+            base::FieldTrial::MakeName("Net.HttpJob.TotalTimeCached",
+                                       "OverlappedReadImpact"),
+            total_time);
+      } else  {
+        UMA_HISTOGRAM_TIMES(
+            base::FieldTrial::MakeName("Net.HttpJob.TotalTimeNotCached",
+                                       "OverlappedReadImpact"),
+            total_time);
+      }
+    }
+  }
+
   start_time_ = base::TimeTicks();
 }
 
 void URLRequestHttpJob::DoneWithRequest(CompletionCause reason) {
   if (done_)
     return;
   done_ = true;
 
   RecordPerfHistograms(reason);
   if (reason == FINISHED)
@@ skipping 10 matching lines @@
 
 void URLRequestHttpJob::NotifyURLRequestDestroyed() {
   awaiting_callback_ = false;
 }
 
 void URLRequestHttpJob::OnDetachRequest() {
   http_transaction_delegate_->OnDetachRequest();
 }
 
 }  // namespace net