Remove tcmalloc when not being used. Restore shim on Windows.

build/common.gypi

 # Copyright (c) 2012 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 1240 matching lines @@
 
     # Set to 1 to enable running Android lint on java/class files.
     'android_lint%': 1,
 
     # Although base/allocator lets you select a heap library via an
     # environment variable, the libcmt shim it uses sometimes gets in
     # the way.  To disable it entirely, and switch to normal msvcrt, do e.g.
     #  'win_use_allocator_shim': 0,
     #  'win_release_RuntimeLibrary': 2
     # to ~/.gyp/include.gypi, gclient runhooks --force, and do a release build.
-    'win_use_allocator_shim%': 0, # 1 = shim allocator via libcmt; 0 = msvcrt
+    'win_use_allocator_shim%': 1, # 1 = shim allocator via libcmt; 0 = msvcrt
 
     # TODO(bradnelson): eliminate this when possible.
     # To allow local gyp files to prevent release.vsprops from being included.
     # Yes(1) means include release.vsprops.
     # Once all vsprops settings are migrated into gyp, this can go away.
     'msvs_use_common_release%': 1,
 
     # TODO(bradnelson): eliminate this when possible.
     # To allow local gyp files to override additional linker options for msvs.
     # Yes(1) means set use the common linker options.
@@ skipping 1489 matching lines @@
         'defines': [
           'DONT_EMBED_BUILD_METADATA',
         ],
       }],  # dont_embed_build_metadata==1
       ['dcheck_always_on!=0', {
         'defines': ['DCHECK_ALWAYS_ON=1'],
       }],  # dcheck_always_on!=0
       ['tracing_like_official_build!=0', {
         'defines': ['TRACING_IS_OFFICIAL_BUILD=1'],
       }],  # tracing_like_official_build!=0
-      ['win_use_allocator_shim==0', {
+      ['OS=="win"', {
+        'defines': ['NO_TCMALLOC'],
         'conditions': [
-          ['OS=="win"', {
-            'defines': ['NO_TCMALLOC'],
+          ['win_use_allocator_shim==1', {
+            'defines': ['ALLOCATOR_SHIM'],
           }],
         ],
       }],
       ['asan==1', {
         'defines': [
           'ADDRESS_SANITIZER',
           'MEMORY_TOOL_REPLACES_ALLOCATOR',
           'MEMORY_SANITIZER_INITIAL_SIZE',
         ],
       }],
@@ skipping 637 matching lines @@
               'DYNAMIC_ANNOTATIONS_ENABLED=0',
             ],
           }, {
             'defines': [
               'MEMORY_TOOL_REPLACES_ALLOCATOR',
               'MEMORY_SANITIZER_INITIAL_SIZE',
               'DYNAMIC_ANNOTATIONS_ENABLED=1',
               'WTF_USE_DYNAMIC_ANNOTATIONS=1',
             ],
           }],
-          ['OS=="win" and win_use_allocator_shim==0', {
+          ['OS=="win"', {
             'defines': ['NO_TCMALLOC'],
           }],
           # _FORTIFY_SOURCE isn't really supported by Clang now, see
           # http://llvm.org/bugs/show_bug.cgi?id=16821.
           # It seems to work fine with Ubuntu 12 headers though, so use it
           # in official builds.
           ['os_posix==1 and (asan!=1 and msan!=1 and tsan!=1 and lsan!=1 and ubsan!=1) and (OS!="linux" or clang!=1 or buildtype=="Official")', {
             'target_conditions': [
               ['chromium_code==1', {
                 # Non-chromium code is not guaranteed to compile cleanly
@@ skipping 2401 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }