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/RTCVideoSource.mm b/webrtc/sdk/objc/Framework/Classes/RTCVideoSource.mm
new file mode 100644
index 0000000..eddf5e0
--- /dev/null
+++ b/webrtc/sdk/objc/Framework/Classes/RTCVideoSource.mm
@@ -0,0 +1,82 @@
+/*
+ *  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 "RTCVideoSource+Private.h"
+
+@implementation RTCVideoSource {
+  rtc::scoped_refptr<webrtc::VideoTrackSourceInterface> _nativeVideoSource;
+}
+
+- (RTCSourceState)state {
+  return [[self class] sourceStateForNativeState:_nativeVideoSource->state()];
+}
+
+- (NSString *)description {
+  return [NSString stringWithFormat:@"RTCVideoSource:\n%@",
+                                    [[self class] stringForState:self.state]];
+}
+
+#pragma mark - Private
+
+- (rtc::scoped_refptr<webrtc::VideoTrackSourceInterface>)nativeVideoSource {
+  return _nativeVideoSource;
+}
+
+- (instancetype)initWithNativeVideoSource:
+    (rtc::scoped_refptr<webrtc::VideoTrackSourceInterface>)nativeVideoSource {
+  NSParameterAssert(nativeVideoSource);
+  if (self = [super init]) {
+    _nativeVideoSource = nativeVideoSource;
+  }
+  return self;
+}
+
++ (webrtc::MediaSourceInterface::SourceState)nativeSourceStateForState:
+    (RTCSourceState)state {
+  switch (state) {
+    case RTCSourceStateInitializing:
+      return webrtc::MediaSourceInterface::kInitializing;
+    case RTCSourceStateLive:
+      return webrtc::MediaSourceInterface::kLive;
+    case RTCSourceStateEnded:
+      return webrtc::MediaSourceInterface::kEnded;
+    case RTCSourceStateMuted:
+      return webrtc::MediaSourceInterface::kMuted;
+  }
+}
+
++ (RTCSourceState)sourceStateForNativeState:
+    (webrtc::MediaSourceInterface::SourceState)nativeState {
+  switch (nativeState) {
+    case webrtc::MediaSourceInterface::kInitializing:
+      return RTCSourceStateInitializing;
+    case webrtc::MediaSourceInterface::kLive:
+      return RTCSourceStateLive;
+    case webrtc::MediaSourceInterface::kEnded:
+      return RTCSourceStateEnded;
+    case webrtc::MediaSourceInterface::kMuted:
+      return RTCSourceStateMuted;
+  }
+}
+
++ (NSString *)stringForState:(RTCSourceState)state {
+  switch (state) {
+    case RTCSourceStateInitializing:
+      return @"Initializing";
+    case RTCSourceStateLive:
+      return @"Live";
+    case RTCSourceStateEnded:
+      return @"Ended";
+    case RTCSourceStateMuted:
+      return @"Muted";
+  }
+}
+
+@end