Hookup the generic heap intercept for Windows.

build/config/allocator.gni

Index: build/config/allocator.gni
diff --git a/build/config/allocator.gni b/build/config/allocator.gni
index 10ac1adf0bd32b80a7bda79525769ed9dea2d68b..79350e5b4a7bcaf327fe4d36a4d1a004f45164bc 100644
--- a/build/config/allocator.gni
+++ b/build/config/allocator.gni
@@ -32,6 +32,12 @@ declare_args() {
 assert(use_allocator == "none" || use_allocator == "tcmalloc")
 
 assert(!is_win || use_allocator == "none", "Tcmalloc doesn't work on Windows.")
-assert(
-    !use_experimental_allocator_shim || is_linux || is_android,
-    "use_experimental_allocator_shim supported only on Linux and Android targets")
+
+# NaCL doesn't obey any of this configuration.

[Sigurður Ásgeirsson, 2016/07/11 19:51:51]

I don't know that this is the right thing to do.
Maybe the build flag argument needs to be separated from the flag used to
propagate the setting, and the latter set to false for nacl?

+if (!(is_win && is_nacl)) {
+  assert(
+      !use_experimental_allocator_shim || is_linux || is_android || is_win,
+      "use_experimental_allocator_shim supported only on Linux, Android and Windows targets")
+}
+# TODO(siggi): assert that the experimental allocator is only enabled for
+#     non-component builds on Windows.