ObjC: Split out NV12 texture uploading into separate class

webrtc/sdk/objc/Framework/Classes/RTCNV12TextureCache.h

Index: webrtc/sdk/objc/Framework/Classes/RTCNV12TextureCache.h
diff --git a/webrtc/sdk/objc/Framework/Classes/RTCNV12TextureCache.h b/webrtc/sdk/objc/Framework/Classes/RTCNV12TextureCache.h
new file mode 100644
index 0000000000000000000000000000000000000000..747c2eb94993056f965c978e9bee56e69379ecd7
--- /dev/null
+++ b/webrtc/sdk/objc/Framework/Classes/RTCNV12TextureCache.h
@@ -0,0 +1,26 @@
+/*
+ *  Copyright 2017 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 "WebRTC/RTCVideoFrame.h"
+
+#import <GLKit/GLKit.h>
+
+@interface RTCNV12TextureCache : NSObject
+
+@property(nonatomic, readonly) GLuint yTexture;
+@property(nonatomic, readonly) GLuint uvTexture;
+
+- (instancetype)initWithContext:(EAGLContext *)context;
+
+- (BOOL)uploadFrameToTextures:(RTCVideoFrame *)frame;
+
+- (void)releaseTextures;
+
+@end