Add a simple about:tcmalloc page that just displays its canned stats....

build/build_config.h

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file adds defines about the platform we're currently building on.
 //  Operating System:
 //    OS_WIN / OS_MACOSX / OS_LINUX / OS_POSIX (MACOSX or LINUX)
 //  Compiler:
 //    COMPILER_MSVC / COMPILER_GCC
 //  Processor:
@@ skipping 36 matching lines @@
 // Use NSS for crypto.
 #if defined(OS_LINUX) || defined(OS_FREEBSD)
 #define USE_NSS 1
 #endif
 
 // Use X11 (and hence GTK/GDK)
 #if defined(OS_LINUX) || defined(OS_FREEBSD)
 #define USE_X11 1
 #endif
 
+// Use tcmalloc
+#if defined(OS_WIN) && ! defined(NO_TCMALLOC)
+#define USE_TCMALLOC 1
+#endif
+
 // Compiler detection.
 #if defined(__GNUC__)
 #define COMPILER_GCC 1
 #elif defined(_MSC_VER)
 #define COMPILER_MSVC 1
 #else
 #error Please add support for your compiler in build/build_config.h
 #endif
 
 // Processor architecture detection.  For more info on what's defined, see:
@@ skipping 22 matching lines @@
 #define WCHAR_T_IS_UTF16
 #elif defined(OS_POSIX) && defined(COMPILER_GCC) && \
     defined(__WCHAR_MAX__) && \
     (__WCHAR_MAX__ == 0x7fffffff || __WCHAR_MAX__ == 0xffffffff)
 #define WCHAR_T_IS_UTF32
 #else
 #error Please add support for your compiler in build/build_config.h
 #endif
 
 #endif  // BUILD_BUILD_CONFIG_H_