More instrumentation to track down net/ jank.

net/proxy/proxy_script_fetcher_impl.cc

Index: net/proxy/proxy_script_fetcher_impl.cc
diff --git a/net/proxy/proxy_script_fetcher_impl.cc b/net/proxy/proxy_script_fetcher_impl.cc
index 7d5d1ff84551e0fa137407c412370948eaa74ba4..8ef777abe05595d05acf02ef9edec7d600b881fb 100644
--- a/net/proxy/proxy_script_fetcher_impl.cc
+++ b/net/proxy/proxy_script_fetcher_impl.cc
@@ -7,6 +7,7 @@
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/strings/string_util.h"
 #include "net/base/data_url.h"
 #include "net/base/io_buffer.h"
@@ -114,6 +115,11 @@ void ProxyScriptFetcherImpl::OnResponseCompleted(URLRequest* request) {
 
 int ProxyScriptFetcherImpl::Fetch(
     const GURL& url, base::string16* text, const CompletionCallback& callback) {
+  // TODO(eroman): Remove ScopedTracker below once crbug.com/455942 is fixed.
+  tracked_objects::ScopedTracker tracking_profile1(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "455942 ProxyScriptFetcherImpl::Fetch (Other)"));
+
   // It is invalid to call Fetch() while a request is already in progress.
   DCHECK(!cur_request_.get());
   DCHECK(!callback.is_null());
@@ -121,6 +127,10 @@ int ProxyScriptFetcherImpl::Fetch(
 
   // Handle base-64 encoded data-urls that contain custom PAC scripts.
   if (url.SchemeIs("data")) {
+    // TODO(eroman): Remove ScopedTracker below once crbug.com/455942 is fixed.
+    tracked_objects::ScopedTracker tracking_profile2(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "455942 ProxyScriptFetcherImpl::Fetch (data url)"));
     std::string mime_type;
     std::string charset;
     std::string data;
@@ -155,6 +165,12 @@ int ProxyScriptFetcherImpl::Fetch(
 
   // Post a task to timeout this request if it takes too long.
   cur_request_id_ = ++next_id_;
+
+  // TODO(eroman): Remove ScopedTracker below once crbug.com/455942 is fixed.
+  tracked_objects::ScopedTracker tracking_profile3(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "455942 ProxyScriptFetcherImpl::Fetch (PostDelayedTask)"));
+
   base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ProxyScriptFetcherImpl::OnTimeout,