Video capture: Refactor GetBestMatchedFormat from Win to OS independent

media/video/capture/mac/video_capture_device_mac.mm

Index: media/video/capture/mac/video_capture_device_mac.mm
diff --git a/media/video/capture/mac/video_capture_device_mac.mm b/media/video/capture/mac/video_capture_device_mac.mm
index 190f53d6a380a01f4c7bbc6be9af5860f2532d51..65103e5e86f5a6b887dacac73e5d9b51f81c6792 100644
--- a/media/video/capture/mac/video_capture_device_mac.mm
+++ b/media/video/capture/mac/video_capture_device_mac.mm
@@ -20,6 +20,7 @@
 #import "media/video/capture/mac/platform_video_capturing_mac.h"
 #import "media/video/capture/mac/video_capture_device_avfoundation_mac.h"
 #import "media/video/capture/mac/video_capture_device_qtkit_mac.h"
+#include "ui/gfx/size.h"
 
 @implementation DeviceNameAndTransportType
 
@@ -94,24 +95,19 @@ typedef struct IOUSBInterfaceDescriptor {
   UInt8 bUnitID;
 } IOUSBInterfaceDescriptor;
 
-// TODO(ronghuawu): Replace this with CapabilityList::GetBestMatchedCapability.
-void GetBestMatchSupportedResolution(int* width, int* height) {
+static void GetBestMatchSupportedResolution(gfx::Size* resolution) {
   int min_diff = kint32max;
-  int matched_width = *width;
-  int matched_height = *height;
-  int desired_res_area = *width * *height;
+  const int desired_area = resolution->GetArea();
   for (size_t i = 0; i < arraysize(kWellSupportedResolutions); ++i) {
-    int area = kWellSupportedResolutions[i]->width *
-               kWellSupportedResolutions[i]->height;
-    int diff = std::abs(desired_res_area - area);
+    const int area = kWellSupportedResolutions[i]->width *
+                     kWellSupportedResolutions[i]->height;
+    const int diff = std::abs(desired_area - area);
     if (diff < min_diff) {
       min_diff = diff;
-      matched_width = kWellSupportedResolutions[i]->width;
-      matched_height = kWellSupportedResolutions[i]->height;
+      resolution->SetSize(kWellSupportedResolutions[i]->width,
+                          kWellSupportedResolutions[i]->height);
     }
   }
-  *width = matched_width;
-  *height = matched_height;
 }
 
 // Tries to create a user-side device interface for a given USB device. Returns
@@ -370,15 +366,13 @@ void VideoCaptureDeviceMac::AllocateAndStart(
   if (state_ != kIdle) {
     return;
   }
-  int width = params.requested_format.frame_size.width();
-  int height = params.requested_format.frame_size.height();
-  float frame_rate = params.requested_format.frame_rate;
 
   // QTKit API can scale captured frame to any size requested, which would lead
   // to undesired aspect ratio changes. Try to open the camera with a known
   // supported format and let the client crop/pad the captured frames.
+  gfx::Size resolution = params.requested_format.frame_size;
   if (!AVFoundationGlue::IsAVFoundationSupported())
-    GetBestMatchSupportedResolution(&width, &height);
+    GetBestMatchSupportedResolution(&resolution);
 
   client_ = client.Pass();
   if (device_name_.capture_api_type() == Name::AVFOUNDATION)
@@ -394,13 +388,11 @@ void VideoCaptureDeviceMac::AllocateAndStart(
     SetErrorState("Could not open capture device.");
     return;
   }
-  if (frame_rate < kMinFrameRate)
-    frame_rate = kMinFrameRate;
-  else if (frame_rate > kMaxFrameRate)
-    frame_rate = kMaxFrameRate;
 
-  capture_format_.frame_size.SetSize(width, height);
-  capture_format_.frame_rate = frame_rate;
+  capture_format_.frame_size = resolution;
+  capture_format_.frame_rate =
+      std::max(kMinFrameRate,
+               std::min(params.requested_format.frame_rate, kMaxFrameRate));
   capture_format_.pixel_format = PIXEL_FORMAT_UYVY;
 
   // QTKit: Set the capture resolution only if this is VGA or smaller, otherwise
@@ -410,8 +402,8 @@ void VideoCaptureDeviceMac::AllocateAndStart(
   // latency, because the webcam will need to be reopened if its default
   // resolution is not HD or VGA.
   // AVfoundation is configured for all resolutions.
-  if (AVFoundationGlue::IsAVFoundationSupported() || width <= kVGA.width ||
-      height <= kVGA.height) {
+  if (AVFoundationGlue::IsAVFoundationSupported() ||
+      resolution.width() <= kVGA.width || resolution.height() <= kVGA.height) {
     if (!UpdateCaptureResolution())
       return;
   }