Obj-C SDK Cleanup

This CL separates the files under sdk/objc into logical directories, replacing
the previous file layout under Framework/.

A long term goal is to have some system set up to generate the files under
sdk/objc/api (the PeerConnection API wrappers) from the C++ code. In the shorter
term the goal is to abstract out shared concepts from these classes in order to
make them as uniform as possible.

The separation into base/, components/, and helpers/ are to differentiate between
the base layer's common protocols, various utilities and the actual platform
specific components.

The old directory layout that resembled a framework's internal layout is not
necessary, since it is generated by the framework target when building it.

Bug: webrtc:9627
Change-Id: Ib084fd83f050ae980649ca99e841f4fb0580bd8f
Reviewed-on: https://webrtc-review.googlesource.com/94142
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Commit-Queue: Anders Carlsson <andersc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24493}
diff --git a/sdk/objc/Framework/Headers/WebRTC/RTCMTLVideoView.h b/sdk/objc/Framework/Headers/WebRTC/RTCMTLVideoView.h
index 0615495..9f43dc5 100644
--- a/sdk/objc/Framework/Headers/WebRTC/RTCMTLVideoView.h
+++ b/sdk/objc/Framework/Headers/WebRTC/RTCMTLVideoView.h
@@ -8,44 +8,4 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#import <Foundation/Foundation.h>
-
-#import "WebRTC/RTCVideoFrame.h"
-#import "WebRTC/RTCVideoRenderer.h"
-
-// Check if metal is supported in WebRTC.
-// NOTE: Currently arm64 == Metal.
-#if defined(__aarch64__)
-#define RTC_SUPPORTS_METAL
-#endif
-
-NS_ASSUME_NONNULL_BEGIN
-
-/**
- * RTCMTLVideoView is thin wrapper around MTKView.
- *
- * It has id<RTCVideoRenderer> property that renders video frames in the view's
- * bounds using Metal.
- * NOTE: always check if metal is available on the running device via
- * RTC_SUPPORTS_METAL macro before initializing this class.
- */
-NS_CLASS_AVAILABLE_IOS(9)
-
-RTC_EXPORT
-@interface RTCMTLVideoView : UIView<RTCVideoRenderer>
-
-@property(nonatomic, weak) id<RTCVideoViewDelegate> delegate;
-
-@property(nonatomic) UIViewContentMode videoContentMode;
-
-/** @abstract Enables/disables rendering.
- */
-@property(nonatomic, getter=isEnabled) BOOL enabled;
-
-/** @abstract Wrapped RTCVideoRotation, or nil.
- */
-@property(nonatomic, nullable) NSValue* rotationOverride;
-
-@end
-
-NS_ASSUME_NONNULL_END
+#import "components/renderer/metal/RTCMTLVideoView.h"