Adding instrumentation to locate the source of jankiness.

content/browser/loader/resource_dispatcher_host_impl.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.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 
 #include <algorithm>
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/debug/alias.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/shared_memory.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/stl_util.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "content/browser/appcache/appcache_interceptor.h"
 #include "content/browser/appcache/chrome_appcache_service.h"
 #include "content/browser/cert_store_impl.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/download/download_resource_handler.h"
 #include "content/browser/download/save_file_manager.h"
 #include "content/browser/download/save_file_resource_handler.h"
 #include "content/browser/fileapi/chrome_blob_storage_context.h"
@@ skipping 2110 matching lines @@
     if (view)  // The view could be gone at this point.
       view->LoadStateChanged(i->second.url, i->second.load_state,
                              i->second.upload_position,
                              i->second.upload_size);
   }
 }
 
 }  // namespace
 
 void ResourceDispatcherHostImpl::UpdateLoadStates() {
+  // TODO(pkasting): Remove ScopedTracker below once crbug.com/455952 is
+  // fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "455952 ResourceDispatcherHostImpl::UpdateLoadStates"));
   // Populate this map with load state changes, and then send them on to the UI
   // thread where they can be passed along to the respective RVHs.
   LoadInfoMap info_map;
 
   LoaderMap::const_iterator i;
 
   // Determine the largest upload size of all requests
   // in each View (good chance it's zero).
   std::map<GlobalRoutingID, uint64> largest_upload_size;
   for (i = pending_loaders_.begin(); i != pending_loaders_.end(); ++i) {
@@ skipping 204 matching lines @@
 
   // Add a flag to selectively bypass the data reduction proxy if the resource
   // type is not an image.
   if (request_data.resource_type != RESOURCE_TYPE_IMAGE)
     load_flags |= net::LOAD_BYPASS_DATA_REDUCTION_PROXY;
 
   return load_flags;
 }
 
 }  // namespace content