Move RTCI420Frame to webrtc/api/objc/RTCVideoFrame with minor style changes.

BUG=
R=tkchin@webrtc.org

Review URL: https://codereview.webrtc.org/1533193003 .

Patch from Jon Hjelle <hjon@andyet.net>.

Cr-Commit-Position: refs/heads/master@{#11203}
diff --git a/webrtc/api/objc/RTCVideoFrame.mm b/webrtc/api/objc/RTCVideoFrame.mm
new file mode 100644
index 0000000..db2d07b
--- /dev/null
+++ b/webrtc/api/objc/RTCVideoFrame.mm
@@ -0,0 +1,79 @@
+/*
+ *  Copyright 2015 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 "RTCVideoFrame.h"
+
+#include "webrtc/base/scoped_ptr.h"
+
+#import "webrtc/api/objc/RTCVideoFrame+Private.h"
+
+@implementation RTCVideoFrame {
+  rtc::scoped_ptr<cricket::VideoFrame> _videoFrame;
+}
+
+- (size_t)width {
+  return _videoFrame->GetWidth();
+}
+
+- (size_t)height {
+  return _videoFrame->GetHeight();
+}
+
+- (size_t)chromaWidth {
+  return _videoFrame->GetChromaWidth();
+}
+
+- (size_t)chromaHeight {
+  return _videoFrame->GetChromaHeight();
+}
+
+- (size_t)chromaSize {
+  return _videoFrame->GetChromaSize();
+}
+
+- (const uint8_t *)yPlane {
+  const cricket::VideoFrame *const_frame = _videoFrame.get();
+  return const_frame->GetYPlane();
+}
+
+- (const uint8_t *)uPlane {
+  const cricket::VideoFrame *const_frame = _videoFrame.get();
+  return const_frame->GetUPlane();
+}
+
+- (const uint8_t *)vPlane {
+  const cricket::VideoFrame *const_frame = _videoFrame.get();
+  return const_frame->GetVPlane();
+}
+
+- (int32_t)yPitch {
+  return _videoFrame->GetYPitch();
+}
+
+- (int32_t)uPitch {
+  return _videoFrame->GetUPitch();
+}
+
+- (int32_t)vPitch {
+  return _videoFrame->GetVPitch();
+}
+
+#pragma mark - Private
+
+- (instancetype)initWithNativeFrame:(const cricket::VideoFrame *)nativeFrame {
+  if (self = [super init]) {
+    // Keep a shallow copy of the video frame. The underlying frame buffer is
+    // not copied.
+    _videoFrame.reset(nativeFrame->Copy());
+  }
+  return self;
+}
+
+@end