Implement a ScopedThreadHeapUsage class to allow profiling per-thread heap usage.

base/allocator/allocator_shim_default_dispatch_to_glibc.cc

Index: base/allocator/allocator_shim_default_dispatch_to_glibc.cc
diff --git a/base/allocator/allocator_shim_default_dispatch_to_glibc.cc b/base/allocator/allocator_shim_default_dispatch_to_glibc.cc
index 02facbad2eb7cff333e4f9ab6a78b5cffeb52632..f3a535973989e234f0a9c325dd93b3f0475bc68e 100644
--- a/base/allocator/allocator_shim_default_dispatch_to_glibc.cc
+++ b/base/allocator/allocator_shim_default_dispatch_to_glibc.cc
@@ -4,6 +4,8 @@
 
 #include "base/allocator/allocator_shim.h"
 
+#include <malloc.h>
+
 // This translation unit defines a default dispatch for the allocator shim which
 // routes allocations to libc functions.
 // The code here is strongly inspired from tcmalloc's libc_override_glibc.h.
@@ -40,13 +42,20 @@ void GlibcFree(const AllocatorDispatch*, void* address) {
   __libc_free(address);
 }
 
+size_t GlibcGetSizeEstimate(const AllocatorDispatch*, void* address) {
+  // TODO(siggi, primiano): malloc_usable_size may need redirection in the
+  //     presence of interposing shims that divert allocations.
+  return malloc_usable_size(address);
+}
+
 }  // namespace
 
 const AllocatorDispatch AllocatorDispatch::default_dispatch = {
-    &GlibcMalloc,   /* alloc_function */
-    &GlibcCalloc,   /* alloc_zero_initialized_function */
-    &GlibcMemalign, /* alloc_aligned_function */
-    &GlibcRealloc,  /* realloc_function */
-    &GlibcFree,     /* free_function */
-    nullptr,        /* next */
+    &GlibcMalloc,          /* alloc_function */
+    &GlibcCalloc,          /* alloc_zero_initialized_function */
+    &GlibcMemalign,        /* alloc_aligned_function */
+    &GlibcRealloc,         /* realloc_function */
+    &GlibcFree,            /* free_function */
+    &GlibcGetSizeEstimate, /* get_size_estimate_function */
+    nullptr,               /* next */
 };