Implement mac version of AppRTCDemo.

- Refactored and moved AppRTCDemo to support sharing AppRTC connection code between iOS and mac counterparts.
- Refactored OpenGL rendering code to be shared between iOS and mac counterparts.
- iOS AppRTCDemo now respects video aspect ratio.

BUG=2168
R=fischman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/17589004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6291 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/talk/examples/objc/AppRTCDemo/APPRTCAppClient.h b/talk/examples/objc/AppRTCDemo/APPRTCAppClient.h
new file mode 100644
index 0000000..b69b517
--- /dev/null
+++ b/talk/examples/objc/AppRTCDemo/APPRTCAppClient.h
@@ -0,0 +1,68 @@
+/*
+ * libjingle
+ * Copyright 2013, Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import "GAEChannelClient.h"
+
+@class APPRTCAppClient;
+@protocol APPRTCAppClientDelegate
+
+- (void)appClient:(APPRTCAppClient*)appClient
+    didErrorWithMessage:(NSString*)message;
+- (void)appClient:(APPRTCAppClient*)appClient
+    didReceiveICEServers:(NSArray*)servers;
+
+@end
+
+@class RTCMediaConstraints;
+
+// Negotiates signaling for chatting with apprtc.appspot.com "rooms".
+// Uses the client<->server specifics of the apprtc AppEngine webapp.
+//
+// To use: create an instance of this object (registering a message handler) and
+// call connectToRoom().  apprtc.appspot.com will signal that is successful via
+// onOpen through the browser channel.  Then you should call sendData() and wait
+// for the registered handler to be called with received messages.
+@interface APPRTCAppClient : NSObject<NSURLConnectionDataDelegate>
+
+@property(nonatomic) BOOL initiator;
+@property(nonatomic, copy, readonly) RTCMediaConstraints* videoConstraints;
+@property(nonatomic, weak) id<APPRTCAppClientDelegate> delegate;
+
+- (id)initWithDelegate:(id<APPRTCAppClientDelegate>)delegate
+        messageHandler:(id<GAEMessageHandler>)handler;
+- (void)connectToRoom:(NSURL*)room;
+- (void)sendData:(NSData*)data;
+
+#ifndef DOXYGEN_SHOULD_SKIP_THIS
+// Disallow init and don't add to documentation
+- (id)init __attribute__((
+    unavailable("init is not a supported initializer for this class.")));
+#endif /* DOXYGEN_SHOULD_SKIP_THIS */
+
+@end