Refactor Extension initialization logic. Add tracing and additional histogram.

chrome/browser/extensions/component_loader.cc

Index: chrome/browser/extensions/component_loader.cc
diff --git a/chrome/browser/extensions/component_loader.cc b/chrome/browser/extensions/component_loader.cc
index 0d431c2a45da8e4b3bca9f8fbb70a23535db8a70..3c40959a3641563bb8e878059c173e3d14bccf62 100644
--- a/chrome/browser/extensions/component_loader.cc
+++ b/chrome/browser/extensions/component_loader.cc
@@ -133,14 +133,13 @@ ComponentLoader::~ComponentLoader() {
 
 void ComponentLoader::LoadAll() {
   TRACE_EVENT0("browser,startup", "ComponentLoader::LoadAll");
-  const base::TimeTicks start_time = base::TimeTicks::Now();
+  SCOPED_UMA_HISTOGRAM_TIMER("Extensions.LoadAllComponentTime");
+
   for (RegisteredComponentExtensions::iterator it =
           component_extensions_.begin();
       it != component_extensions_.end(); ++it) {
     Load(*it);
   }
-  UMA_HISTOGRAM_TIMES("Extensions.LoadAllComponentTime",
-                      base::TimeTicks::Now() - start_time);
 }
 
 base::DictionaryValue* ComponentLoader::ParseManifest(