Add memory heap checks for mediaserver and audioserver

Memory heap check updated and restored to mediaserver,
added as new option to audioserver.

Requires properties to be set (example for audioserver):

$ adb shell setprop libc.debug.malloc.program audioserver
$ adb shell setprop libc.debug.malloc.options backtrace=8
$ adb shell pkill audioserver

...

and to dump:

$ adb shell dumpsys media.audio_flinger -m

Bug: 28909124
Bug: 27500825
Change-Id: Ifa8c2c02b022daf1a799ee4a1d75282a3c921763
diff --git a/include/media/MemoryLeakTrackUtil.h b/include/media/MemoryLeakTrackUtil.h
index d2618aa..4c1a60c 100644
--- a/include/media/MemoryLeakTrackUtil.h
+++ b/include/media/MemoryLeakTrackUtil.h
@@ -16,11 +16,16 @@
 #ifndef MEMORY_LEAK_TRACK_UTIL_H
 #define MEMORY_LEAK_TRACK_UTIL_H
 
+#include <iostream>
+
 namespace android {
 /*
- * Dump the memory address of the calling process to the given fd.
+ * Dump the heap memory of the calling process, sorted by total size
+ * (allocation size * number of allocations).
+ *
+ *    limit is the number of unique allocations to return.
  */
-extern void dumpMemoryAddresses(int fd);
+extern std::string dumpMemoryAddresses(size_t limit);
 
 };