Video capture: Refactor GetBestMatchedFormat from Win to OS independent

media/video/capture/video_capture_types.cc

Index: media/video/capture/video_capture_types.cc
diff --git a/media/video/capture/video_capture_types.cc b/media/video/capture/video_capture_types.cc
index 39ca75527ed7a7a9eb220a09dc8476aa1c411cd4..4ab586a9f3c8b7f9385855258395c960972d3c82 100644
--- a/media/video/capture/video_capture_types.cc
+++ b/media/video/capture/video_capture_types.cc
@@ -4,6 +4,8 @@
 
 #include "media/video/capture/video_capture_types.h"
 
+#include <cmath>
+
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "media/base/limits.h"
@@ -69,4 +71,35 @@ std::string VideoCaptureFormat::PixelFormatToString(VideoPixelFormat format) {
 
 VideoCaptureParams::VideoCaptureParams() : allow_resolution_change(false) {}
 
+namespace {
+struct DiffVideoCaptureFormat {
+  DiffVideoCaptureFormat(const VideoCaptureFormat& requested,
+                         const VideoCaptureFormat& supported)
+      : diff_width(std::abs(requested.frame_size.width() -
+                            supported.frame_size.width())),
+        diff_height(std::abs(requested.frame_size.height() -
+                             supported.frame_size.height())),
+        diff_frame_rate(std::fabs(requested.frame_rate -
+                                  supported.frame_rate)) {}
+  int diff_width;

[tommi (sloooow) - chröme, 2014/09/09 20:11:10]

make all of these const?

+  int diff_height;
+  float diff_frame_rate;
+};
+}  // namespace.
+
+CompareVideoFormat::CompareVideoFormat(const VideoCaptureFormat& requested)
+    : requested_(requested) {}
+
+bool CompareVideoFormat::operator()(
+    const VideoCaptureFormat& lhs_format,
+    const VideoCaptureFormat& rhs_format) const {
+  const DiffVideoCaptureFormat lhs(requested_, lhs_format);
+  const DiffVideoCaptureFormat rhs(requested_, rhs_format);
+  if (lhs.diff_height != rhs.diff_height)
+    return lhs.diff_height < rhs.diff_height;
+  if (lhs.diff_width != rhs.diff_width)
+    return lhs.diff_width < rhs.diff_width;
+  return lhs.diff_frame_rate < rhs.diff_frame_rate;
+}
+
 }  // namespace media