[NOT TO COMMIT!] Replace third_party/tcmalloc/chromium with tcmalloc r136 (the latest).

third_party/tcmalloc/chromium/src/system-alloc.h

Index: third_party/tcmalloc/chromium/src/system-alloc.h
diff --git a/third_party/tcmalloc/chromium/src/system-alloc.h b/third_party/tcmalloc/chromium/src/system-alloc.h
index 0432b32ebd9f452a310ea3de33bf59ace812c7ad..814b5564dc7d1d68c0503d058e78d64d54a0eb28 100644
--- a/third_party/tcmalloc/chromium/src/system-alloc.h
+++ b/third_party/tcmalloc/chromium/src/system-alloc.h
@@ -71,17 +71,6 @@ extern void* TCMalloc_SystemAlloc(size_t bytes, size_t *actual_bytes,
 // be released, partial pages will not.)
 extern void TCMalloc_SystemRelease(void* start, size_t length);
 
-// Called to ressurect memory which has been previously released
-// to the system via TCMalloc_SystemRelease.  An attempt to
-// commit a page that is already committed does not cause this
-// function to fail.
-extern void TCMalloc_SystemCommit(void* start, size_t length);
-
-// Guards the first page in the supplied range of memory and returns the size
-// of the guard page. Will return 0 if a guard cannot be added to the page
-// (e.g. start is not aligned or size is not large enough).
-extern size_t TCMalloc_SystemAddGuard(void* start, size_t size);
-
 // The current system allocator.
 extern PERFTOOLS_DLL_DECL SysAllocator* sys_alloc;