Add native memory accounting through custom allocator.

Added a custom allocator that lets you pass in a special tag which
specifices where the allocation came from. This is used when
dumping. The performance overhead is low since each allocation only
does a atomic add/sub for each allocation/free.

The measurements are dumped to traces.txt during SIGQUIT.

Example output:
I/art     (27274): AllocatorTagHeap active=120 max=120 total=168
I/art     (27274): AllocatorTagMonitorList active=1572 max=6240 total=11724
I/art     (27274): AllocatorTagClassTable active=185208 max=185208 total=268608
I/art     (27274): AllocatorTagInternTable active=430368 max=430368 total=436080
I/art     (27274): AllocatorTagMaps active=5616 max=6168 total=34392
I/art     (27274): AllocatorTagLOS active=1024 max=1536 total=2044
I/art     (27274): AllocatorTagSafeMap active=0 max=51936 total=533688
I/art     (27274): AllocatorTagLOSMaps active=144 max=1248 total=5760
I/art     (27274): AllocatorTagReferenceTable active=10944 max=11840 total=19136
I/art     (27274): AllocatorTagHeapBitmap active=32 max=40 total=56
I/art     (27274): AllocatorTagHeapBitmapLOS active=8 max=8 total=8
I/art     (27274): AllocatorTagVerifier active=0 max=18844 total=1073156
I/art     (27274): AllocatorTagModUnionCardSet active=5300 max=5920 total=56020
I/art     (27274): AllocatorTagModUnionReferenceArray active=24864 max=24864 total=24864
I/art     (27274): AllocatorTagJNILibrarires active=320 max=320 total=320
I/art     (27274): AllocatorTagOatFile active=1400 max=1400 total=5852

Change-Id: Ibb470ef2e9c9a24563bb46422d46a55799704d82

(cherry picked from commit 5369c40f75fdcb1be7a7c06db212ce965c83a164)
diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index c7d6060..2f86799 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -22,6 +22,7 @@
 #include <utility>
 #include <vector>
 
+#include "base/allocator.h"
 #include "base/macros.h"
 #include "base/mutex.h"
 #include "dex_file.h"
@@ -632,7 +633,7 @@
   // multimap from a string hash code of a class descriptor to
   // mirror::Class* instances. Results should be compared for a matching
   // Class::descriptor_ and Class::class_loader_.
-  typedef std::multimap<size_t, GcRoot<mirror::Class>> Table;
+  typedef AllocationTrackingMultiMap<size_t, GcRoot<mirror::Class>, kAllocatorTagClassTable> Table;
   // This contains strong roots. To enable concurrent root scanning of
   // the class table, be careful to use a read barrier when accessing this.
   Table class_table_ GUARDED_BY(Locks::classlinker_classes_lock_);