Update the tcmalloc vendor branch to r144 (gperftools 2.0), and README.chromium.

third_party/tcmalloc/vendor/src/gperftools/malloc_extension.h

Index: third_party/tcmalloc/vendor/src/gperftools/malloc_extension.h
diff --git a/third_party/tcmalloc/vendor/src/google/malloc_extension.h b/third_party/tcmalloc/vendor/src/gperftools/malloc_extension.h
similarity index 93%
copy from third_party/tcmalloc/vendor/src/google/malloc_extension.h
copy to third_party/tcmalloc/vendor/src/gperftools/malloc_extension.h
index 4b06b2d951a0cc6305a98712b9f05fb51a72279b..b180115ff34cbe0bd52c9c92cefffdb129ec20d5 100644
--- a/third_party/tcmalloc/vendor/src/google/malloc_extension.h
+++ b/third_party/tcmalloc/vendor/src/gperftools/malloc_extension.h
@@ -100,10 +100,9 @@ class PERFTOOLS_DLL_DECL MallocExtension {
 
   // See "verify_memory.h" to see what these routines do
   virtual bool VerifyAllMemory();
-  // TODO(csilvers): change these to const void*.
-  virtual bool VerifyNewMemory(void* p);
-  virtual bool VerifyArrayNewMemory(void* p);
-  virtual bool VerifyMallocMemory(void* p);
+  virtual bool VerifyNewMemory(const void* p);
+  virtual bool VerifyArrayNewMemory(const void* p);
+  virtual bool VerifyMallocMemory(const void* p);
   virtual bool MallocMemoryStats(int* blocks, size_t* total,
                                  int histogram[kMallocHistogramSize]);
 
@@ -170,6 +169,26 @@ class PERFTOOLS_DLL_DECL MallocExtension {
   //      Number of bytes used across all thread caches.
   //      This property is not writable.
   //
+  // "tcmalloc.central_cache_free_bytes"
+  //      Number of free bytes in the central cache that have been
+  //      assigned to size classes. They always count towards virtual
+  //      memory usage, and unless the underlying memory is swapped out
+  //      by the OS, they also count towards physical memory usage.
+  //      This property is not writable.
+  //
+  // "tcmalloc.transfer_cache_free_bytes"
+  //      Number of free bytes that are waiting to be transfered between
+  //      the central cache and a thread cache. They always count
+  //      towards virtual memory usage, and unless the underlying memory
+  //      is swapped out by the OS, they also count towards physical
+  //      memory usage. This property is not writable.
+  //
+  // "tcmalloc.thread_cache_free_bytes"
+  //      Number of free bytes in thread caches. They always count
+  //      towards virtual memory usage, and unless the underlying memory
+  //      is swapped out by the OS, they also count towards physical
+  //      memory usage. This property is not writable.
+  //
   // "tcmalloc.pageheap_free_bytes"
   //      Number of bytes in free, mapped pages in page heap.  These
   //      bytes can be used to fulfill allocation requests.  They
@@ -281,8 +300,7 @@ class PERFTOOLS_DLL_DECL MallocExtension {
   // will return 0.)
   // This is equivalent to malloc_size() in OS X, malloc_usable_size()
   // in glibc, and _msize() for windows.
-  // TODO(csilvers): change to const void*.
-  virtual size_t GetAllocatedSize(void* p);
+  virtual size_t GetAllocatedSize(const void* p);
 
   // Returns kOwned if this malloc implementation allocated the memory
   // pointed to by p, or kNotOwned if some other malloc implementation