fake_video_capture_device_factory.cc: Change loop to range based

Test= FakeVideoCaptureDeviceTest in media_unittests

Review URL: https://codereview.chromium.org/1033733009

Cr-Commit-Position: refs/heads/master@{#322606}

media/video/capture/fake_video_capture_device_factory.cc

@@ -55,8 +55,8 @@ void FakeVideoCaptureDeviceFactory::GetDeviceSupportedFormats(
                                        gfx::Size(1280, 720),
                                        gfx::Size(1920, 1080)};
   supported_formats->clear();
-  for (size_t i = 0; i < arraysize(supported_sizes); ++i) {
-    supported_formats->push_back(VideoCaptureFormat(supported_sizes[i],
+  for (const auto& size : supported_sizes) {
+    supported_formats->push_back(VideoCaptureFormat(size,
                                                     frame_rate,
                                                     media::PIXEL_FORMAT_I420));
   }