Made device orientation mandatory for locking capture orientation in …

…the platform interface.

packages/camera/camera_platform_interface/lib/src/method_channel/method_channel_camera.dart

@@ -159,8 +159,8 @@ class MethodChannelCamera extends CameraPlatform {
   }
 
   @override
-  Future<void> lockCaptureOrientation(int cameraId,
-      [DeviceOrientation orientation]) async {
+  Future<void> lockCaptureOrientation(
+      int cameraId, DeviceOrientation orientation) async {
     await _channel.invokeMethod<String>(
       'lockCaptureOrientation',
       <String, dynamic>{

packages/camera/camera_platform_interface/lib/src/platform_interface/camera_platform.dart

@@ -87,10 +87,8 @@ abstract class CameraPlatform extends PlatformInterface {
   }
 
   /// Locks the capture orientation.
-  ///
-  /// If [orientation] is omitted, the current device orientation is used.
-  Future<void> lockCaptureOrientation(int cameraId,
-      [DeviceOrientation orientation]) {
+  Future<void> lockCaptureOrientation(
+      int cameraId, DeviceOrientation orientation) {
     throw UnimplementedError('lockCaptureOrientation() is not implemented.');
   }
 

packages/camera/camera_platform_interface/lib/src/utils/utils.dart

@@ -16,7 +16,6 @@ CameraLensDirection parseCameraLensDirection(String string) {
 
 /// Returns the device orientation as a String.
 String serializeDeviceOrientation(DeviceOrientation orientation) {
-  if (orientation == null) return null;
   switch (orientation) {
     case DeviceOrientation.portraitUp:
       return 'portraitUp';
@@ -33,7 +32,6 @@ String serializeDeviceOrientation(DeviceOrientation orientation) {
 
 /// Returns the device orientation for a given String.
 DeviceOrientation deserializeDeviceOrientation(String str) {
-  if (str == null) return null;
   switch (str) {
     case "portraitUp":
       return DeviceOrientation.portraitUp;

packages/camera/camera_platform_interface/test/camera_platform_interface_test.dart

@@ -117,7 +117,7 @@ void main() {
 
       // Act & Assert
       expect(
-        () => cameraPlatform.lockCaptureOrientation(1),
+        () => cameraPlatform.lockCaptureOrientation(1, null),
         throwsUnimplementedError,
       );
     });

packages/camera/camera_platform_interface/test/method_channel/method_channel_camera_test.dart

@@ -803,14 +803,11 @@ void main() {
         );
 
         // Act
-        await camera.lockCaptureOrientation(cameraId);
         await camera.lockCaptureOrientation(
             cameraId, DeviceOrientation.portraitUp);
 
         // Assert
         expect(channel.log, <Matcher>[
-          isMethodCall('lockCaptureOrientation',
-              arguments: {'cameraId': cameraId, 'orientation': null}),
           isMethodCall('lockCaptureOrientation',
               arguments: {'cameraId': cameraId, 'orientation': 'portraitUp'}),
         ]);

packages/camera/camera_platform_interface/test/utils/utils_test.dart

@@ -32,7 +32,6 @@ void main() {
     });
 
     test("serializeDeviceOrientation() should serialize correctly", () {
-      expect(serializeDeviceOrientation(null), null);
       expect(serializeDeviceOrientation(DeviceOrientation.portraitUp),
           "portraitUp");
       expect(serializeDeviceOrientation(DeviceOrientation.portraitDown),
@@ -44,7 +43,6 @@ void main() {
     });
 
     test("deserializeDeviceOrientation() should deserialize correctly", () {
-      expect(deserializeDeviceOrientation(null), null);
       expect(deserializeDeviceOrientation('portraitUp'),
           DeviceOrientation.portraitUp);
       expect(deserializeDeviceOrientation('portraitDown'),