Cherry-pick 49ad76e. rdar://problem/109220107

    [iOS] AVCatpureDeviceManager should set userPreferrerCamera
    https://bugs.webkit.org/show_bug.cgi?id=256882
    rdar://109220107

    Reviewed by Eric Carlson.

    Before https://bugs.webkit.org/show_bug.cgi?id=255451, we were forcing the default camera to be the front camera using media constraints.
    This was blocking edfaulting to higher priority cameras, hence the fix.
    The drawback is that we are now fully relying on systemPreferredCamera to select the default camera.
    systemPreferredCamera might change depending on which camera was last used by the application.
    We do not want that behavior, so we use userPreferredCamera to state that we are more interested in the front camera than in the back cameras.
    Other camneras should still be higher priority if available.

    Manually tested.

    * Source/WebCore/platform/mediastream/mac/AVCaptureDeviceManager.h:
    * Source/WebCore/platform/mediastream/mac/AVCaptureDeviceManager.mm:
    (WebCore::AVCaptureDeviceManager::computeCaptureDevices):
    (WebCore::AVCaptureDeviceManager::refreshCaptureDevicesInternal):
    (WebCore::AVCaptureDeviceManager::setUserPreferredCamera):
    (WebCore::AVCaptureDeviceManager::refreshCaptureDevices): Deleted.

    Canonical link: https://commits.webkit.org/264165@main

Identifier: 263769.41@safari-7616.1.14.10-branch

Source/WebCore/platform/mediastream/mac/AVCaptureDeviceManager.h

@@ -50,7 +50,7 @@ class AVCaptureDeviceManager final : public CaptureDeviceManager {
 public:
     static AVCaptureDeviceManager& singleton();
 
-    void refreshCaptureDevices(CompletionHandler<void()>&& = [] { });
+    void refreshCaptureDevices() { refreshCaptureDevicesInternal([] { }, ShouldSetUserPreferredCamera::No); };
 
 private:
     static bool isAvailable();
@@ -66,6 +66,10 @@ class AVCaptureDeviceManager final : public CaptureDeviceManager {
     Vector<CaptureDevice> retrieveCaptureDevices();
     RetainPtr<NSArray> currentCameras();
 
+    enum class ShouldSetUserPreferredCamera : bool { No, Yes };
+    void refreshCaptureDevicesInternal(CompletionHandler<void()>&&, ShouldSetUserPreferredCamera);
+    void setUserPreferredCamera();
+
     RetainPtr<WebCoreAVCaptureDeviceManagerObserver> m_objcObserver;
     Vector<CaptureDevice> m_devices;
     RetainPtr<NSMutableArray> m_avCaptureDevices;

Source/WebCore/platform/mediastream/mac/AVCaptureDeviceManager.mm

@@ -62,10 +62,10 @@ -(void)observeValueForKeyPath:keyPath ofObject:(id)object change:(NSDictionary*)
 void AVCaptureDeviceManager::computeCaptureDevices(CompletionHandler<void()>&& callback)
 {
     if (!m_isInitialized) {
-        refreshCaptureDevices([this, callback = WTFMove(callback)]() mutable {
+        refreshCaptureDevicesInternal([this, callback = WTFMove(callback)]() mutable {
             m_isInitialized = true;
             callback();
-        });
+        }, ShouldSetUserPreferredCamera::Yes);
         return;
     }
     callback();
@@ -208,9 +208,11 @@ static inline bool isVideoDevice(AVCaptureDevice *device)
     return deviceList;
 }
 
-void AVCaptureDeviceManager::refreshCaptureDevices(CompletionHandler<void()>&& callback)
+void AVCaptureDeviceManager::refreshCaptureDevicesInternal(CompletionHandler<void()>&& callback, ShouldSetUserPreferredCamera shouldSetUserPreferredCamera)
 {
-    m_dispatchQueue->dispatch([this, callback = WTFMove(callback)]() mutable {
+    m_dispatchQueue->dispatch([this, callback = WTFMove(callback), shouldSetUserPreferredCamera]() mutable {
+        if (shouldSetUserPreferredCamera == ShouldSetUserPreferredCamera::Yes)
+            setUserPreferredCamera();
         RunLoop::main().dispatch([this, callback = WTFMove(callback), deviceList = crossThreadCopy(retrieveCaptureDevices())]() mutable {
             bool deviceHasChanged = m_devices.size() != deviceList.size();
             if (!deviceHasChanged) {
@@ -260,6 +262,21 @@ static inline bool isVideoDevice(AVCaptureDevice *device)
     [PAL::getAVCaptureDeviceDiscoverySessionClass() removeObserver:m_objcObserver.get() forKeyPath:@"devices"];
 }
 
+void AVCaptureDeviceManager::setUserPreferredCamera()
+{
+#if PLATFORM(IOS_FAMILY)
+    if ([PAL::getAVCaptureDeviceClass() respondsToSelector:@selector(setUserPreferredCamera:)]) {
+        auto currentDevices = currentCameras();
+        for (AVCaptureDevice *platformDevice in currentDevices.get()) {
+            if (isVideoDevice(platformDevice) && [platformDevice position] == AVCaptureDevicePositionFront) {
+                [PAL::getAVCaptureDeviceClass() setUserPreferredCamera:platformDevice];
+                break;
+            }
+        }
+    }
+#endif
+}
+
 void AVCaptureDeviceManager::registerForDeviceNotifications()
 {
     [[NSNotificationCenter defaultCenter] addObserver:m_objcObserver.get() selector:@selector(deviceConnectedDidChange:) name:AVCaptureDeviceWasConnectedNotification object:nil];