Measure browser->render->browser hop time in UMA.

content/browser/loader/async_resource_handler.h

Index: content/browser/loader/async_resource_handler.h
diff --git a/content/browser/loader/async_resource_handler.h b/content/browser/loader/async_resource_handler.h
index 6842b192ccadfdb847a555a2dea525c9fc036043..ecf3a23b0959e62589866d52a402617a0cd1209c 100644
--- a/content/browser/loader/async_resource_handler.h
+++ b/content/browser/loader/async_resource_handler.h
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "base/memory/ref_counted.h"
+#include "base/time/time.h"
 #include "content/browser/loader/resource_handler.h"
 #include "content/browser/loader/resource_message_delegate.h"
 #include "url/gurl.h"
@@ -78,6 +79,8 @@ class AsyncResourceHandler : public ResourceHandler,
 
   int64_t reported_transfer_size_;
 
+  base::TimeTicks redirect_start_time_;
+
   DISALLOW_COPY_AND_ASSIGN(AsyncResourceHandler);
 };