Add _android files for building DartVM on Android

runtime/bin/dbg_connection.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef BIN_DBG_CONNECTION_H_
 #define BIN_DBG_CONNECTION_H_
 
 #include "bin/builtin.h"
 #include "bin/utils.h"
 
 #include "include/dart_debugger_api.h"
 
 #include "platform/globals.h"
 #include "platform/json.h"
 #include "platform/thread.h"
 // Declare the OS-specific types ahead of defining the generic class.
-#if defined(TARGET_OS_LINUX)
+#if defined(TARGET_OS_ANDROID)
+#include "bin/dbg_connection_android.h"
+#elif defined(TARGET_OS_LINUX)
 #include "bin/dbg_connection_linux.h"
 #elif defined(TARGET_OS_MACOS)
 #include "bin/dbg_connection_macos.h"
 #elif defined(TARGET_OS_WINDOWS)
 #include "bin/dbg_connection_win.h"
 #else
 #error Unknown target os.
 #endif
 
 
@@ skipping 70 matching lines @@
 
   static MessageBuffer* msgbuf_;
 
   friend class DebuggerConnectionImpl;
 
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(DebuggerConnectionHandler);
 };
 
 #endif  // BIN_DBG_CONNECTION_H_