Build dynamic iOS SDK.

- Places most ObjC code into webrtc/sdk/objc instead.
- New gyp targets to build, strip and export symbols for dylib.
- Removes old script used to generate dylib.

BUG=

Review URL: https://codereview.webrtc.org/1903663002

Cr-Commit-Position: refs/heads/master@{#12524}
diff --git a/webrtc/sdk/objc/Framework/Classes/RTCVideoFrame.mm b/webrtc/sdk/objc/Framework/Classes/RTCVideoFrame.mm
new file mode 100644
index 0000000..8a99d4e
--- /dev/null
+++ b/webrtc/sdk/objc/Framework/Classes/RTCVideoFrame.mm
@@ -0,0 +1,117 @@
+/*
+ *  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+Private.h"
+
+#include "webrtc/base/scoped_ptr.h"
+
+@implementation RTCVideoFrame {
+  rtc::scoped_ptr<cricket::VideoFrame> _videoFrame;
+  rtc::scoped_refptr<webrtc::VideoFrameBuffer> _i420Buffer;
+}
+
+- (size_t)width {
+  return _videoFrame->width();
+}
+
+- (size_t)height {
+  return _videoFrame->height();
+}
+
+// TODO(nisse): chromaWidth and chromaHeight are used only in
+// RTCOpenGLVideoRenderer.mm. Update, and then delete these
+// properties.
+- (size_t)chromaWidth {
+  return (self.width + 1) / 2;
+}
+
+- (size_t)chromaHeight {
+  return (self.height + 1) / 2;
+}
+
+- (const uint8_t *)yPlane {
+  if (!self.i420Buffer) {
+    return nullptr;
+  }
+  return self.i420Buffer->data(webrtc::kYPlane);
+}
+
+- (const uint8_t *)uPlane {
+  if (!self.i420Buffer) {
+    return nullptr;
+  }
+  return self.i420Buffer->data(webrtc::kUPlane);
+}
+
+- (const uint8_t *)vPlane {
+  if (!self.i420Buffer) {
+    return nullptr;
+  }
+  return self.i420Buffer->data(webrtc::kVPlane);
+}
+
+- (int32_t)yPitch {
+  if (!self.i420Buffer) {
+    return 0;
+  }
+  return self.i420Buffer->stride(webrtc::kYPlane);
+}
+
+- (int32_t)uPitch {
+  if (!self.i420Buffer) {
+    return 0;
+  }
+  return self.i420Buffer->stride(webrtc::kUPlane);
+}
+
+- (int32_t)vPitch {
+  if (!self.i420Buffer) {
+    return 0;
+  }
+  return self.i420Buffer->stride(webrtc::kVPlane);
+}
+
+- (int64_t)timeStamp {
+  return _videoFrame->GetTimeStamp();
+}
+
+- (CVPixelBufferRef)nativeHandle {
+  return static_cast<CVPixelBufferRef>(_videoFrame->GetNativeHandle());
+}
+
+- (void)convertBufferIfNeeded {
+  if (!_i420Buffer) {
+    if (_videoFrame->GetNativeHandle()) {
+      // Convert to I420.
+      _i420Buffer = _videoFrame->video_frame_buffer()->NativeToI420Buffer();
+    } else {
+      // Should already be I420.
+      _i420Buffer = _videoFrame->video_frame_buffer();
+    }
+  }
+}
+
+#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;
+}
+
+- (rtc::scoped_refptr<webrtc::VideoFrameBuffer>)i420Buffer {
+  [self convertBufferIfNeeded];
+  return _i420Buffer;
+}
+
+@end