Hookup the generic heap intercept for Windows.

base/allocator/BUILD.gn

 # Copyright (c) 2013 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.
 
 import("//build/buildflag_header.gni")
 import("//build/config/allocator.gni")
 import("//build/config/compiler/compiler.gni")
 
 declare_args() {
   # Provide a way to force disable debugallocation in Debug builds,
   # e.g. for profiling (it's more rare to profile Debug builds,
   # but people sometimes need to do that).
   enable_debugallocation = is_debug
 }
 
-# Allocator shim is only enabled for Release static builds.
-win_use_allocator_shim = is_win && !is_component_build && !is_debug
+# The Windows-only allocator shim is only enabled for Release static builds, and
+# is mutually exclusive with the generalized shim.
+win_use_allocator_shim = is_win && !is_component_build && !is_debug &&
+                         !use_experimental_allocator_shim
 
 # This "allocator" meta-target will forward to the default allocator according
 # to the build settings.
 group("allocator") {
   public_deps = []
   deps = []
 
   if (use_allocator == "tcmalloc") {
     deps += [ ":tcmalloc" ]
   }
 
   if (win_use_allocator_shim) {
     public_deps += [ ":allocator_shim" ]
   }
 }
 
 # This config defines ALLOCATOR_SHIM in the same conditions that the allocator
 # shim will be used by the allocator target.
 #
 # TODO(brettw) this is only used in one place and is kind of mess, because it
 # assumes that the library using it will eventually be linked with
 # //base/allocator in the default way. Clean this up and delete this.
 config("allocator_shim_define") {
-  if (win_use_allocator_shim) {
-    defines = [ "ALLOCATOR_SHIM" ]
-  }
+  defines = [ "ALLOCATOR_SHIM" ]

[Primiano Tucci (use gerrit), 2016/07/12 14:51:04]

If I am understanding this correctly you are dropping this if so you can recycle
the define for the tests.
See my proposal on the top, let's have a different define for the tests, in the
allocator features buildflag header.

[Sigurður Ásgeirsson, 2016/07/14 19:04:26]

Done.

 }
 
 config("tcmalloc_flags") {
   defines = []
   if (enable_debugallocation) {
     defines += [
       # Use debugallocation for Debug builds to catch problems early
       # and cleanly, http://crbug.com/30715 .
       "TCMALLOC_FOR_DEBUGALLOCATION",
     ]
@@ skipping 18 matching lines @@
       "-Wno-unused-private-field",
     ]
   }
 }
 
 # This config is only used on Windows static release builds for the
 # allocator shim.
 if (win_use_allocator_shim) {
   source_set("allocator_shim") {
     sources = [
+      "allocator_impl_win.cc",

[Primiano Tucci (use gerrit), 2016/07/12 14:51:04]

I think just for the sake of making all these files less obscure this should
have winheap in the name. 
Maybe: winheap_stubs_win.h/cc ? or something similar

[Sigurður Ásgeirsson, 2016/07/14 19:04:26]

Done.

+      "allocator_impl_win.h",
       "allocator_shim_win.cc",
       "allocator_shim_win.h",
     ]
     configs += [ ":allocator_shim_define" ]
   }
 }
 
 if (use_allocator == "tcmalloc") {
   # tcmalloc currently won't compile on Android.
   source_set("tcmalloc") {
@@ skipping 203 matching lines @@
     # Linux/CrOS/Android. http://crbug.com/550886 .
     configs += [ "//base:base_implementation" ]  # for BASE_EXPORT
     visibility = [ "//base:base" ]
     sources = [
       "allocator_shim.cc",
       "allocator_shim.h",
       "allocator_shim_internals.h",
       "allocator_shim_override_cpp_symbols.h",
       "allocator_shim_override_libc_symbols.h",
     ]
-    if (is_linux && use_allocator == "tcmalloc") {
+    if (is_win) {
+      sources += [
+        "allocator_impl_win.cc",
+        "allocator_impl_win.h",
+      ]
+
+      # This gates tests that require the presence of the allocator shim.
+      configs += [ ":allocator_shim_define" ]

[Primiano Tucci (use gerrit), 2016/07/12 14:51:04]

if you follow my suggestion above about having the
ENABLE_WIN_ALLOCATOR_SHIM_TESTS in the features there is not need for this line,
as the allocator features are already a dep of base.

[Sigurður Ásgeirsson, 2016/07/14 19:04:26]

Done.

+    }
+    if (is_win) {
+      sources += [ "allocator_shim_default_dispatch_to_winheap.cc" ]
+    } else if (is_linux && use_allocator == "tcmalloc") {
       sources += [
         "allocator_shim_default_dispatch_to_tcmalloc.cc",
         "allocator_shim_override_glibc_weak_symbols.h",
       ]
       deps = [
         ":tcmalloc",
       ]
     } else if (is_linux && use_allocator == "none") {
       sources += [ "allocator_shim_default_dispatch_to_glibc.cc" ]
     } else if (is_android && use_allocator == "none") {
       sources += [
         "allocator_shim_default_dispatch_to_linker_wrapped_symbols.cc",
         "allocator_shim_override_linker_wrapped_symbols.h",
       ]
       all_dependent_configs = [ ":wrap_malloc_symbols" ]
     }
   }
 }