Move FileEnumerator to its own file, do some refactoring.

gpu/config/gpu_info_collector_win.cc

Index: gpu/config/gpu_info_collector_win.cc
diff --git a/gpu/config/gpu_info_collector_win.cc b/gpu/config/gpu_info_collector_win.cc
index b55ebe721ab41208f1e08e45b12712aea4badd66..5fcdc9f712a33e3e45ed36c23ff68d3614bc56ca 100644
--- a/gpu/config/gpu_info_collector_win.cc
+++ b/gpu/config/gpu_info_collector_win.cc
@@ -17,6 +17,7 @@
 #include "base/debug/trace_event.h"
 #include "base/metrics/field_trial.h"
 #include "base/file_util.h"
+#include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
@@ -80,10 +81,10 @@ GpuPerformanceStats RetrieveGpuPerformanceStats() {
   }
 
   // Find most recent formal assessment results.
-  file_util::FileEnumerator file_enumerator(
+  base::FileEnumerator file_enumerator(
       base::FilePath(winsat_results_path),
       false,  // not recursive
-      file_util::FileEnumerator::FILES,
+      base::FileEnumerator::FILES,
       FILE_PATH_LITERAL("* * Formal.Assessment (*).WinSAT.xml"));
 
   base::FilePath current_results;