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}

webrtc/sdk/objc/Framework/Classes/RTCAVFoundationVideoSource.mm

@@ -0,0 +1,55 @@
+/*
+ *  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 "RTCAVFoundationVideoSource+Private.h"
+
+#import "RTCMediaConstraints+Private.h"
+#import "RTCPeerConnectionFactory+Private.h"
+#import "RTCVideoSource+Private.h"
+
+@implementation RTCAVFoundationVideoSource {
+  webrtc::AVFoundationVideoCapturer *_capturer;
+}
+
+- (instancetype)initWithFactory:(RTCPeerConnectionFactory *)factory
+                    constraints:(RTCMediaConstraints *)constraints {
+  NSParameterAssert(factory);
+  // We pass ownership of the capturer to the source, but since we own
+  // the source, it should be ok to keep a raw pointer to the
+  // capturer.
+  _capturer = new webrtc::AVFoundationVideoCapturer();
+  rtc::scoped_refptr<webrtc::VideoTrackSourceInterface> source =
+      factory.nativeFactory->CreateVideoSource(
+          _capturer, constraints.nativeConstraints.get());
+
+  return [super initWithNativeVideoSource:source];
+}
+
+- (BOOL)canUseBackCamera {
+  return self.capturer->CanUseBackCamera();
+}
+
+- (BOOL)useBackCamera {
+  return self.capturer->GetUseBackCamera();
+}
+
+- (void)setUseBackCamera:(BOOL)useBackCamera {
+  self.capturer->SetUseBackCamera(useBackCamera);
+}
+
+- (AVCaptureSession *)captureSession {
+  return self.capturer->GetCaptureSession();
+}
+
+- (webrtc::AVFoundationVideoCapturer *)capturer {
+  return _capturer;
+}
+
+@end