Remove extern "C" barriers to using C++.

Change-Id: Ic046d6aa540738cb46b54531bc59ba3b47b0136d
diff --git a/adb/adb.h b/adb/adb.h
index 749515c..cb2cf60 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -23,10 +23,6 @@
 #include "adb_trace.h"
 #include "fdevent.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #define MAX_PAYLOAD 4096
 
 #define A_SYNC 0x434e5953
@@ -47,14 +43,8 @@
 // Increment this when we want to force users to start a new adb server.
 #define ADB_SERVER_VERSION 32
 
-typedef struct amessage amessage;
-typedef struct apacket apacket;
-typedef struct asocket asocket;
-typedef struct alistener alistener;
-typedef struct aservice aservice;
-typedef struct atransport atransport;
-typedef struct adisconnect  adisconnect;
-typedef struct usb_handle usb_handle;
+struct atransport;
+struct usb_handle;
 
 struct amessage {
     unsigned command;       /* command identifier constant      */
@@ -171,12 +161,12 @@
 ** object, it's a special value used to indicate that a client wants to
 ** connect to a service implemented within the ADB server itself.
 */
-typedef enum transport_type {
+enum transport_type {
         kTransportUsb,
         kTransportLocal,
         kTransportAny,
         kTransportHost,
-} transport_type;
+};
 
 #define TOKEN_SIZE 20
 
@@ -363,10 +353,10 @@
 extern int HOST;
 extern int SHELL_EXIT_NOTIFY_FD;
 
-typedef enum {
+enum subproc_mode {
     SUBPROC_PTY = 0,
     SUBPROC_RAW = 1,
-} subproc_mode;
+} ;
 
 #define CHUNK_SIZE (64*1024)
 
@@ -389,8 +379,4 @@
 
 void send_connect(atransport *t);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif