Fixes for re-enabling more MSVC level 4 warnings: Source/core/ edition

Source/core/BUILD.gn

 # 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.
 
 import("//build/config/ui.gni")
 import("//third_party/WebKit/Source/bindings/bindings.gni")
 import("//third_party/WebKit/Source/bindings/core/v8/generated.gni")
 import("//third_party/WebKit/Source/bindings/modules/modules.gni")
 import("//third_party/WebKit/Source/bindings/modules/v8/generated.gni")
 import("//third_party/WebKit/Source/bindings/scripts/scripts.gni")
@@ skipping 455 matching lines @@
   defines = []
 
   if (is_win && component_mode == "shared_library") {
     defines += [ "USING_V8_SHARED" ]
   }
 
   if (is_win) {
     cflags += [
       # In generated bindings code: "switch contains default but no case".
       # Disable c4267 warnings until we fix size_t to int truncations.
-      # 4702 is disabled because of issues in Bison-generated
+      # 4701 and 4702 are disabled because of issues in Bison-generated
       # XPathGrammar.cpp and CSSGrammar.cpp.
       "/wd4065",
       "/wd4267",
+      "/wd4701",
       "/wd4702",
     ]
   }
 
   # TODO(GYP) More IPP libraries, see above.
   #if ((is_linux || is_android) && use_webaudio_ipp)
   #  ["OS in ("linux", "android") and "WTF_USE_WEBAUDIO_IPP=1" in feature_defines", {
   #    "cflags": [
   #      "<!@(pkg-config --cflags-only-I ipp)",
   #    ],
@@ skipping 638 matching lines @@
     "$blink_core_output_dir/{{source_name_part}}.h",
   ]
   args = [
     "{{source}}",
     rel_blink_core_gen_dir,
     bison_exe,
   ]
 
   deps = make_core_generated_deps
 }