Rename media constraints model and store.

ARDMediaConstraintsModel -> ARDSettingsModel
ARDMediaConstraintsSettingsStore -> ARDSettingsStore
ARDMediaConstraintsModelTests -> ARDSettingsModelTests

Both classes will be used to storing other settings as well, so we need a
more appropriate naming.

BUG=webrtc:6654

Review-Url: https://codereview.webrtc.org/2479153002
Cr-Commit-Position: refs/heads/master@{#15002}
diff --git a/webrtc/examples/objc/AppRTCMobile/ios/ARDSettingsModel+Private.h b/webrtc/examples/objc/AppRTCMobile/ios/ARDSettingsModel+Private.h
new file mode 100644
index 0000000..eba99d7
--- /dev/null
+++ b/webrtc/examples/objc/AppRTCMobile/ios/ARDSettingsModel+Private.h
@@ -0,0 +1,22 @@
+/*
+ *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#import <Foundation/Foundation.h>
+#import "ARDSettingsModel.h"
+
+@class ARDSettingsStore;
+
+NS_ASSUME_NONNULL_BEGIN
+@interface ARDSettingsModel ()
+- (ARDSettingsStore *)settingsStore;
+- (nullable NSString *)currentVideoResolutionWidthFromStore;
+- (nullable NSString *)currentVideoResolutionHeightFromStore;
+@end
+NS_ASSUME_NONNULL_END