Remove stack trace from URLFetcher / URLRequest for debugging

net/url_request/url_fetcher_core.h

Index: net/url_request/url_fetcher_core.h
diff --git a/net/url_request/url_fetcher_core.h b/net/url_request/url_fetcher_core.h
index 243de0a5c79db5a2116ceb7262362922659df5e8..9bd6ce1ecd4e77ef2f7e52ed73ffddcfb23ee0e8 100644
--- a/net/url_request/url_fetcher_core.h
+++ b/net/url_request/url_fetcher_core.h
@@ -12,7 +12,6 @@
 #include <string>
 
 #include "base/compiler_specific.h"
-#include "base/debug/stack_trace.h"
 #include "base/files/file_path.h"
 #include "base/lazy_instance.h"
 #include "base/macros.h"
@@ -347,9 +346,6 @@ class URLFetcherCore : public base::RefCountedThreadSafe<URLFetcherCore>,
   // Total expected bytes to receive (-1 if it cannot be determined).
   int64_t total_response_bytes_;
 
-  // TODO(willchan): Get rid of this after debugging crbug.com/90971.
-  base::debug::StackTrace stack_trace_;
-
   static base::LazyInstance<Registry> g_registry;
 
   DISALLOW_COPY_AND_ASSIGN(URLFetcherCore);