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/helpers/UIDevice+RTCDevice.h b/sdk/objc/helpers/UIDevice+RTCDevice.h
new file mode 100644
index 0000000..eb39ea9
--- /dev/null
+++ b/sdk/objc/helpers/UIDevice+RTCDevice.h
@@ -0,0 +1,81 @@
+/*
+ *  Copyright 2016 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 <UIKit/UIKit.h>
+
+typedef NS_ENUM(NSInteger, RTCDeviceType) {
+  RTCDeviceTypeUnknown,
+  RTCDeviceTypeIPhone1G,
+  RTCDeviceTypeIPhone3G,
+  RTCDeviceTypeIPhone3GS,
+  RTCDeviceTypeIPhone4,
+  RTCDeviceTypeIPhone4Verizon,
+  RTCDeviceTypeIPhone4S,
+  RTCDeviceTypeIPhone5GSM,
+  RTCDeviceTypeIPhone5GSM_CDMA,
+  RTCDeviceTypeIPhone5CGSM,
+  RTCDeviceTypeIPhone5CGSM_CDMA,
+  RTCDeviceTypeIPhone5SGSM,
+  RTCDeviceTypeIPhone5SGSM_CDMA,
+  RTCDeviceTypeIPhone6Plus,
+  RTCDeviceTypeIPhone6,
+  RTCDeviceTypeIPhone6S,
+  RTCDeviceTypeIPhone6SPlus,
+  RTCDeviceTypeIPhone7,
+  RTCDeviceTypeIPhone7Plus,
+  RTCDeviceTypeIPhoneSE,
+  RTCDeviceTypeIPhone8,
+  RTCDeviceTypeIPhone8Plus,
+  RTCDeviceTypeIPhoneX,
+  RTCDeviceTypeIPodTouch1G,
+  RTCDeviceTypeIPodTouch2G,
+  RTCDeviceTypeIPodTouch3G,
+  RTCDeviceTypeIPodTouch4G,
+  RTCDeviceTypeIPodTouch5G,
+  RTCDeviceTypeIPodTouch6G,
+  RTCDeviceTypeIPad,
+  RTCDeviceTypeIPad2Wifi,
+  RTCDeviceTypeIPad2GSM,
+  RTCDeviceTypeIPad2CDMA,
+  RTCDeviceTypeIPad2Wifi2,
+  RTCDeviceTypeIPadMiniWifi,
+  RTCDeviceTypeIPadMiniGSM,
+  RTCDeviceTypeIPadMiniGSM_CDMA,
+  RTCDeviceTypeIPad3Wifi,
+  RTCDeviceTypeIPad3GSM_CDMA,
+  RTCDeviceTypeIPad3GSM,
+  RTCDeviceTypeIPad4Wifi,
+  RTCDeviceTypeIPad4GSM,
+  RTCDeviceTypeIPad4GSM_CDMA,
+  RTCDeviceTypeIPad5,
+  RTCDeviceTypeIPad6,
+  RTCDeviceTypeIPadAirWifi,
+  RTCDeviceTypeIPadAirCellular,
+  RTCDeviceTypeIPadAirWifiCellular,
+  RTCDeviceTypeIPadAir2,
+  RTCDeviceTypeIPadMini2GWifi,
+  RTCDeviceTypeIPadMini2GCellular,
+  RTCDeviceTypeIPadMini2GWifiCellular,
+  RTCDeviceTypeIPadMini3,
+  RTCDeviceTypeIPadMini4,
+  RTCDeviceTypeIPadPro9Inch,
+  RTCDeviceTypeIPadPro12Inch,
+  RTCDeviceTypeIPadPro12Inch2,
+  RTCDeviceTypeIPadPro10Inch,
+  RTCDeviceTypeSimulatori386,
+  RTCDeviceTypeSimulatorx86_64,
+};
+
+@interface UIDevice (RTCDevice)
+
++ (RTCDeviceType)deviceType;
++ (BOOL)isIOS11OrLater;
+
+@end