VideoCaptureDeviceAVFoundation: move static functionality to a new utils file.

This change prepares for development of capturer features behind a new flag. Moving static functionality into a separate file allows the capturer implementation to be duped, and the creator to create either implementation based on a flag.

Future CLs will add the flag and perform the duplication.

Bug: chromium:1126690
Change-Id: I8592a2ba81765e999c497eda9a6f09cc644e1423
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2401520Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Commit-Queue: Markus Handell <handellm@google.com>
Cr-Commit-Position: refs/heads/master@{#805965}

media/capture/BUILD.gn

@@ -164,6 +164,8 @@ component("capture_lib") {
     sources += [
       "video/mac/video_capture_device_avfoundation_mac.h",
       "video/mac/video_capture_device_avfoundation_mac.mm",
+      "video/mac/video_capture_device_avfoundation_utils_mac.h",
+      "video/mac/video_capture_device_avfoundation_utils_mac.mm",
       "video/mac/video_capture_device_decklink_mac.h",
       "video/mac/video_capture_device_decklink_mac.mm",
       "video/mac/video_capture_device_factory_mac.h",

media/capture/video/mac/video_capture_device_avfoundation_mac.h

@@ -16,23 +16,12 @@
 
 namespace media {
 class VideoCaptureDeviceMac;
-
-// Find the best capture format from |formats| for the specified dimensions and
-// frame rate. Returns an element of |formats|, or nil.
-AVCaptureDeviceFormat* CAPTURE_EXPORT
-FindBestCaptureFormat(NSArray<AVCaptureDeviceFormat*>* formats,
-                      int width,
-                      int height,
-                      float frame_rate);
 }  // namespace media
 
 // Class used by VideoCaptureDeviceMac (VCDM) for video and image capture using
 // AVFoundation API. This class lives inside the thread created by its owner
 // VCDM.
 //
-//  * Clients (VCDM) should call +deviceNames to fetch the list of devices
-//    available in the system; this method returns the list of device names that
-//    have to be used with -setCaptureDevice:.
 //  * Previous to any use, clients (VCDM) must call -initWithFrameReceiver: to
 //    initialise an object of this class and register a |frameReceiver_|.
 //  * Frame receiver registration or removal can also happen via explicit call
@@ -86,13 +75,6 @@ FindBestCaptureFormat(NSArray<AVCaptureDeviceFormat*>* formats,
   base::ThreadChecker _main_thread_checker;
 }
 
-// Returns a dictionary of capture devices with friendly name and unique id.
-+ (NSDictionary*)deviceNames;
-
-// Retrieve the capture supported formats for a given device |descriptor|.
-+ (void)getDevice:(const media::VideoCaptureDeviceDescriptor&)descriptor
-    supportedFormats:(media::VideoCaptureFormats*)formats;
-
 // Initializes the instance and the underlying capture session and registers the
 // frame receiver.
 - (id)initWithFrameReceiver:(media::VideoCaptureDeviceMac*)frameReceiver;

media/capture/video/mac/video_capture_device_avfoundation_utils_mac.h

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_CAPTURE_VIDEO_MAC_VIDEO_CAPTURE_DEVICE_AVFOUNDATION_UTILS_MAC_H_
+#define MEDIA_CAPTURE_VIDEO_MAC_VIDEO_CAPTURE_DEVICE_AVFOUNDATION_UTILS_MAC_H_
+
+#import <AVFoundation/AVFoundation.h>
+#import <CoreMedia/CoreMedia.h>
+#import <CoreVideo/CoreVideo.h>
+
+#include "base/mac/scoped_nsobject.h"
+#include "media/capture/video/video_capture_device_descriptor.h"
+#include "media/capture/video_capture_types.h"
+
+namespace media {
+
+// Find the best capture format from |formats| for the specified dimensions and
+// frame rate. Returns an element of |formats|, or nil.
+AVCaptureDeviceFormat* CAPTURE_EXPORT
+FindBestCaptureFormat(NSArray<AVCaptureDeviceFormat*>* formats,
+                      int width,
+                      int height,
+                      float frame_rate);
+
+// Returns a dictionary of capture devices with friendly name and unique id.
+// VideoCaptureDeviceMac should call this function to fetch the list of devices
+// available in the system; this method returns the list of device names that
+// have to be used with -[VideoCaptureDeviceAVFoundation setCaptureDevice:].
+base::scoped_nsobject<NSDictionary> GetVideoCaptureDeviceNames();
+
+// Retrieve the capture supported formats for a given device |descriptor|.
+media::VideoCaptureFormats GetDeviceSupportedFormats(
+    const media::VideoCaptureDeviceDescriptor& descriptor);
+
+// This function translates Mac Core Video pixel formats to Chromium pixel
+// formats.
+media::VideoPixelFormat FourCCToChromiumPixelFormat(FourCharCode code);
+
+// Extracts |base_address| and |length| out of a SampleBuffer.
+void ExtractBaseAddressAndLength(char** base_address,
+                                 size_t* length,
+                                 CMSampleBufferRef sample_buffer);
+
+}  // namespace media
+
+#endif  // MEDIA_CAPTURE_VIDEO_MAC_VIDEO_CAPTURE_DEVICE_AVFOUNDATION_UTILS_MAC_H_

media/capture/video/mac/video_capture_device_factory_mac.mm

@@ -16,6 +16,7 @@
 #include "base/strings/string_util.h"
 #include "base/task_runner_util.h"
 #import "media/capture/video/mac/video_capture_device_avfoundation_mac.h"
+#import "media/capture/video/mac/video_capture_device_avfoundation_utils_mac.h"
 #import "media/capture/video/mac/video_capture_device_decklink_mac.h"
 #include "media/capture/video/mac/video_capture_device_mac.h"
 #include "services/video_capture/public/uma/video_capture_service_event.h"
@@ -102,12 +103,12 @@ void VideoCaptureDeviceFactoryMac::GetDevicesInfo(
 
   // Loop through all available devices and add to |devices_info|.
   std::vector<VideoCaptureDeviceInfo> devices_info;
-  NSDictionary* capture_devices;
   DVLOG(1) << "Enumerating video capture devices using AVFoundation";
-  capture_devices = [VideoCaptureDeviceAVFoundation deviceNames];
+  base::scoped_nsobject<NSDictionary> capture_devices =
+      GetVideoCaptureDeviceNames();
   // Enumerate all devices found by AVFoundation, translate the info for each
   // to class Name and add it to |device_names|.
-  for (NSString* key in capture_devices) {
+  for (NSString* key in capture_devices.get()) {
     const std::string device_id = [key UTF8String];
     const VideoCaptureApi capture_api = VideoCaptureApi::MACOSX_AVFOUNDATION;
     int transport_type = [[capture_devices valueForKey:key] transportType];
@@ -128,9 +129,8 @@ void VideoCaptureDeviceFactoryMac::GetDevicesInfo(
     devices_info.emplace_back(descriptor);
 
     // Get supported formats
-    [VideoCaptureDeviceAVFoundation
-               getDevice:descriptor
-        supportedFormats:&devices_info.back().supported_formats];
+    devices_info.back().supported_formats =
+        GetDeviceSupportedFormats(descriptor);
   }
 
   // Also retrieve Blackmagic devices, if present, via DeckLink SDK API.

media/capture/video/mac/video_capture_device_mac_unittest.mm

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "media/capture/video/mac/video_capture_device_avfoundation_mac.h"
+#include "media/capture/video/mac/video_capture_device_avfoundation_utils_mac.h"
 
 #include "base/mac/scoped_cftyperef.h"
 #include "base/mac/scoped_nsobject.h"