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/RTCDataChannel.mm b/webrtc/sdk/objc/Framework/Classes/RTCDataChannel.mm
new file mode 100644
index 0000000..cdc7e98
--- /dev/null
+++ b/webrtc/sdk/objc/Framework/Classes/RTCDataChannel.mm
@@ -0,0 +1,234 @@
+/*
+ *  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 "RTCDataChannel+Private.h"
+
+#import "NSString+StdString.h"
+
+#include "webrtc/base/scoped_ptr.h"
+
+namespace webrtc {
+
+class DataChannelDelegateAdapter : public DataChannelObserver {
+ public:
+  DataChannelDelegateAdapter(RTCDataChannel *channel) { channel_ = channel; }
+
+  void OnStateChange() override {
+    [channel_.delegate dataChannelDidChangeState:channel_];
+  }
+
+  void OnMessage(const DataBuffer& buffer) override {
+    RTCDataBuffer *data_buffer =
+        [[RTCDataBuffer alloc] initWithNativeBuffer:buffer];
+    [channel_.delegate dataChannel:channel_
+       didReceiveMessageWithBuffer:data_buffer];
+  }
+
+  void OnBufferedAmountChange(uint64_t previousAmount) override {
+    id<RTCDataChannelDelegate> delegate = channel_.delegate;
+    SEL sel = @selector(dataChannel:didChangeBufferedAmount:);
+    if ([delegate respondsToSelector:sel]) {
+      [delegate dataChannel:channel_ didChangeBufferedAmount:previousAmount];
+    }
+  }
+
+ private:
+  __weak RTCDataChannel *channel_;
+};
+}
+
+
+@implementation RTCDataBuffer {
+  rtc::scoped_ptr<webrtc::DataBuffer> _dataBuffer;
+}
+
+- (instancetype)initWithData:(NSData *)data isBinary:(BOOL)isBinary {
+  NSParameterAssert(data);
+  if (self = [super init]) {
+    rtc::CopyOnWriteBuffer buffer(
+        reinterpret_cast<const uint8_t*>(data.bytes), data.length);
+    _dataBuffer.reset(new webrtc::DataBuffer(buffer, isBinary));
+  }
+  return self;
+}
+
+- (NSData *)data {
+  return [NSData dataWithBytes:_dataBuffer->data.data()
+                        length:_dataBuffer->data.size()];
+}
+
+- (BOOL)isBinary {
+  return _dataBuffer->binary;
+}
+
+#pragma mark - Private
+
+- (instancetype)initWithNativeBuffer:(const webrtc::DataBuffer&)nativeBuffer {
+  if (self = [super init]) {
+    _dataBuffer.reset(new webrtc::DataBuffer(nativeBuffer));
+  }
+  return self;
+}
+
+- (const webrtc::DataBuffer *)nativeDataBuffer {
+  return _dataBuffer.get();
+}
+
+@end
+
+
+@implementation RTCDataChannel {
+  rtc::scoped_refptr<webrtc::DataChannelInterface> _nativeDataChannel;
+  rtc::scoped_ptr<webrtc::DataChannelDelegateAdapter> _observer;
+  BOOL _isObserverRegistered;
+}
+
+@synthesize delegate = _delegate;
+
+- (void)dealloc {
+  // Handles unregistering the observer properly. We need to do this because
+  // there may still be other references to the underlying data channel.
+  self.delegate = nil;
+}
+
+- (NSString *)label {
+  return [NSString stringForStdString:_nativeDataChannel->label()];
+}
+
+- (BOOL)isReliable {
+  return _nativeDataChannel->reliable();
+}
+
+- (BOOL)isOrdered {
+  return _nativeDataChannel->ordered();
+}
+
+- (NSUInteger)maxRetransmitTime {
+  return self.maxPacketLifeTime;
+}
+
+- (uint16_t)maxPacketLifeTime {
+  return _nativeDataChannel->maxRetransmitTime();
+}
+
+- (uint16_t)maxRetransmits {
+  return _nativeDataChannel->maxRetransmits();
+}
+
+- (NSString *)protocol {
+  return [NSString stringForStdString:_nativeDataChannel->protocol()];
+}
+
+- (BOOL)isNegotiated {
+  return _nativeDataChannel->negotiated();
+}
+
+- (NSInteger)streamId {
+  return self.channelId;
+}
+
+- (int)channelId {
+  return _nativeDataChannel->id();
+}
+
+- (RTCDataChannelState)readyState {
+  return [[self class] dataChannelStateForNativeState:
+      _nativeDataChannel->state()];
+}
+
+- (uint64_t)bufferedAmount {
+  return _nativeDataChannel->buffered_amount();
+}
+
+- (void)setDelegate:(id<RTCDataChannelDelegate>)delegate {
+  if (_delegate == delegate) {
+    return;
+  }
+  if (_isObserverRegistered) {
+    _nativeDataChannel->UnregisterObserver();
+    _isObserverRegistered = NO;
+  }
+  _delegate = delegate;
+  if (_delegate) {
+    _nativeDataChannel->RegisterObserver(_observer.get());
+    _isObserverRegistered = YES;
+  }
+}
+
+- (void)close {
+  _nativeDataChannel->Close();
+}
+
+- (BOOL)sendData:(RTCDataBuffer *)data {
+  return _nativeDataChannel->Send(*data.nativeDataBuffer);
+}
+
+- (NSString *)description {
+  return [NSString stringWithFormat:@"RTCDataChannel:\n%ld\n%@\n%@",
+                                    (long)self.channelId,
+                                    self.label,
+                                    [[self class]
+                                        stringForState:self.readyState]];
+}
+
+#pragma mark - Private
+
+- (instancetype)initWithNativeDataChannel:
+    (rtc::scoped_refptr<webrtc::DataChannelInterface>)nativeDataChannel {
+  NSParameterAssert(nativeDataChannel);
+  if (self = [super init]) {
+    _nativeDataChannel = nativeDataChannel;
+    _observer.reset(new webrtc::DataChannelDelegateAdapter(self));
+  }
+  return self;
+}
+
++ (webrtc::DataChannelInterface::DataState)
+    nativeDataChannelStateForState:(RTCDataChannelState)state {
+  switch (state) {
+    case RTCDataChannelStateConnecting:
+      return webrtc::DataChannelInterface::DataState::kConnecting;
+    case RTCDataChannelStateOpen:
+      return webrtc::DataChannelInterface::DataState::kOpen;
+    case RTCDataChannelStateClosing:
+      return webrtc::DataChannelInterface::DataState::kClosing;
+    case RTCDataChannelStateClosed:
+      return webrtc::DataChannelInterface::DataState::kClosed;
+  }
+}
+
++ (RTCDataChannelState)dataChannelStateForNativeState:
+    (webrtc::DataChannelInterface::DataState)nativeState {
+  switch (nativeState) {
+    case webrtc::DataChannelInterface::DataState::kConnecting:
+      return RTCDataChannelStateConnecting;
+    case webrtc::DataChannelInterface::DataState::kOpen:
+      return RTCDataChannelStateOpen;
+    case webrtc::DataChannelInterface::DataState::kClosing:
+      return RTCDataChannelStateClosing;
+    case webrtc::DataChannelInterface::DataState::kClosed:
+      return RTCDataChannelStateClosed;
+  }
+}
+
++ (NSString *)stringForState:(RTCDataChannelState)state {
+  switch (state) {
+    case RTCDataChannelStateConnecting:
+      return @"Connecting";
+    case RTCDataChannelStateOpen:
+      return @"Open";
+    case RTCDataChannelStateClosing:
+      return @"Closing";
+    case RTCDataChannelStateClosed:
+      return @"Closed";
+  }
+}
+
+@end