Break a single histogram into two

extensions/browser/extension_protocols.cc

 // Copyright 2014 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 "extensions/browser/extension_protocols.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
 #include "base/base64.h"
 #include "base/compiler_specific.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
+#include "base/metrics/sparse_histogram.h"
 #include "base/path_service.h"
 #include "base/sha1.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/timer/elapsed_timer.h"
 #include "build/build_config.h"
@@ skipping 181 matching lines @@
                    base::Owned(last_modified_time)));
     DCHECK(posted);
   }
 
   virtual void OnSeekComplete(int64 result) OVERRIDE {
     DCHECK_EQ(seek_position_, 0);
     seek_position_ = result;
   }
 
   virtual void OnReadComplete(net::IOBuffer* buffer, int result) OVERRIDE {
-    UMA_HISTOGRAM_COUNTS("ExtensionUrlRequest.OnReadCompleteResult", result);
+    if (result >= 0)
+      UMA_HISTOGRAM_COUNTS("ExtensionUrlRequest.OnReadCompleteResult", result);
+    else
+      UMA_HISTOGRAM_SPARSE_SLOWLY("ExtensionUrlRequest.OnReadCompleteError",
+                                  -result);
     if (result > 0) {
       bytes_read_ += result;
       if (hash_.get()) {
         base::ElapsedTimer timer;
         hash_->Update(buffer->data(), result);
         hashing_time_ += timer.Elapsed();
       }
     }
   }
 
@@ skipping 305 matching lines @@
   return new net::HttpResponseHeaders(raw_headers);
 }
 
 net::URLRequestJobFactory::ProtocolHandler* CreateExtensionProtocolHandler(
     bool is_incognito,
     extensions::InfoMap* extension_info_map) {
   return new ExtensionProtocolHandler(is_incognito, extension_info_map);
 }
 
 }  // namespace extensions