Enable precompiled headers for Blink on Windows

third_party/WebKit/Source/platform/heap/BUILD.gn

Index: third_party/WebKit/Source/platform/heap/BUILD.gn
diff --git a/third_party/WebKit/Source/platform/heap/BUILD.gn b/third_party/WebKit/Source/platform/heap/BUILD.gn
index c2684be56230d992c66200b09143ffdb7681f022..0bdd9ca833f263d6becc0d5d14bffe2690b5076a 100644
--- a/third_party/WebKit/Source/platform/heap/BUILD.gn
+++ b/third_party/WebKit/Source/platform/heap/BUILD.gn
@@ -1,6 +1,6 @@
 # Copyright 2014 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.
+# found in the LICENSE file.
 
 source_set("heap") {
   # This target is a logical part of the platform and only the platform target
@@ -52,6 +52,7 @@ source_set("heap") {
   defines = [ "BLINK_PLATFORM_IMPLEMENTATION=1" ]
 
   configs += [
+    "//third_party/WebKit/Source:blink_pch",
     "//third_party/WebKit/Source:config",
     "//third_party/WebKit/Source:non_test_config",
     "//third_party/WebKit/Source:inside_blink",