dumpsys: display the client PIDs of all of the services

When gathering info on a service, get the BpBinder handle to look up the
node number of the binder service in binder_logs/proc/<pid>.
Look up the node number in binder_logs/state from the binder service.
That entry in the state file has the client PIDs.

Example output:
$ adb shell dumpsys --clients android.hardware.power.IPower/default
Client PIDs: 437, 708, 203

Test: adb root && adb shell dumpsys --clients
Test: adb shell dumpsys --clients power
Test: adb shell dumpsys --clients --pid
Change-Id: I0daebc18cb9f47925ccec5a3eb0b09c4b1e43fe4
diff --git a/cmds/dumpsys/dumpsys.h b/cmds/dumpsys/dumpsys.h
index 05c5d5e..6ab1a7d 100644
--- a/cmds/dumpsys/dumpsys.h
+++ b/cmds/dumpsys/dumpsys.h
@@ -52,10 +52,11 @@
     static void setServiceArgs(Vector<String16>& args, bool asProto, int priorityFlags);
 
     enum Type {
-        TYPE_DUMP = 0x1,      // dump using `dump` function
-        TYPE_PID = 0x2,       // dump pid of server only
-        TYPE_STABILITY = 0x4, // dump stability information of server
-        TYPE_THREAD = 0x8,    // dump thread usage of server only
+        TYPE_DUMP = 0x1,       // dump using `dump` function
+        TYPE_PID = 0x2,        // dump pid of server only
+        TYPE_STABILITY = 0x4,  // dump stability information of server
+        TYPE_THREAD = 0x8,     // dump thread usage of server only
+        TYPE_CLIENTS = 0x10,   // dump pid of clients
     };
 
     /**