Instrumenting copying string returned by GetRawDataResource to locate the source of jankiness.

chrome/browser/extensions/chrome_url_request_util.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 "chrome/browser/extensions/chrome_url_request_util.h"
 
 #include <string>
 
 #include "base/files/file_path.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 57 matching lines @@
         FROM_HERE_WITH_EXPLICIT_FUNCTION(
             "422489 URLRequestResourceBundleJob::GetData"));
 
     const ResourceBundle& rb = ResourceBundle::GetSharedInstance();
 
     // TODO(vadimt): Remove ScopedTracker below once crbug.com/422489 is fixed.
     tracked_objects::ScopedTracker tracking_profile1(
         FROM_HERE_WITH_EXPLICIT_FUNCTION(
             "422489 URLRequestResourceBundleJob::GetData 1"));
 
-    *data = rb.GetRawDataResource(resource_id_).as_string();
+    const base::StringPiece resource_as_string_piece =
+        rb.GetRawDataResource(resource_id_);
+
+    // TODO(vadimt): Remove ScopedTracker below once crbug.com/422489 is fixed.
+    tracked_objects::ScopedTracker tracking_profile15(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "422489 URLRequestResourceBundleJob::GetData 1.5"));
+
+    *data = resource_as_string_piece.as_string();
 
     // TODO(vadimt): Remove ScopedTracker below once crbug.com/422489 is fixed.
     tracked_objects::ScopedTracker tracking_profile2(
         FROM_HERE_WITH_EXPLICIT_FUNCTION(
             "422489 URLRequestResourceBundleJob::GetData 2"));
 
     // Add the Content-Length header now that we know the resource length.
     response_info_.headers->AddHeader(
         base::StringPrintf("%s: %s",
                            net::HttpRequestHeaders::kContentLength,
@@ skipping 116 matching lines @@
                                              resource_id,
                                              content_security_policy,
                                              send_cors_header);
     }
   }
   return NULL;
 }
 
 }  // namespace chrome_url_request_util
 }  // namespace extensions