Update the tcmalloc chromium branch to r144 (gperftools 2.0), and merge chromium-specific changes.

third_party/tcmalloc/chromium/src/static_vars.h

Index: third_party/tcmalloc/chromium/src/static_vars.h
diff --git a/third_party/tcmalloc/chromium/src/static_vars.h b/third_party/tcmalloc/chromium/src/static_vars.h
index b21fe2b2a875bc4b8a314298681456574b555dc2..185a1d45ea80235602b8d902c82f8da2c86986f4 100644
--- a/third_party/tcmalloc/chromium/src/static_vars.h
+++ b/third_party/tcmalloc/chromium/src/static_vars.h
@@ -65,9 +65,7 @@ class Static {
   // must be protected by pageheap_lock.
 
   // Page-level allocator.
-  static PageHeap* pageheap() {
-    return reinterpret_cast<PageHeap*>(pageheap_memory_);
-  }
+  static PageHeap* pageheap() { return pageheap_; }
 
   static PageHeapAllocator<Span>* span_allocator() { return &span_allocator_; }
 
@@ -105,10 +103,7 @@ class Static {
   // is stored in trace->stack[kMaxStackDepth-1].
   static StackTrace* growth_stacks_;
 
-  // PageHeap uses a constructor for initialization.  Like the members above,
-  // we can't depend on initialization order, so pageheap is new'd
-  // into this buffer.
-  static char pageheap_memory_[sizeof(PageHeap)];
+  static PageHeap* pageheap_;
 };
 
 }  // namespace tcmalloc