clang/win: Let some chromium_code targets build with -Wextra.

media/capture/video/win/video_capture_device_mf_win.cc

Index: media/capture/video/win/video_capture_device_mf_win.cc
diff --git a/media/capture/video/win/video_capture_device_mf_win.cc b/media/capture/video/win/video_capture_device_mf_win.cc
index 95595bd16b2e85c313177732a8b2e8c466b82308..77f54f8b9acd34873638ba693d6161f98ec07335 100644
--- a/media/capture/video/win/video_capture_device_mf_win.cc
+++ b/media/capture/video/win/video_capture_device_mf_win.cc
@@ -171,9 +171,9 @@ bool VideoCaptureDeviceMFWin::FormatFromGuid(const GUID& guid,
       {MFVideoFormat_YV12, PIXEL_FORMAT_YV12},
   };
 
-  for (int i = 0; i < arraysize(kFormatMap); ++i) {
-    if (kFormatMap[i].guid == guid) {
-      *format = kFormatMap[i].format;
+  for (const auto& kFormat : kFormatMap) {
+    if (kFormat.guid == guid) {
+      *format = kFormat.format;
       return true;
     }
   }