Use V8GeneratedCoreBindings only in jumbo build

This is retry of
https://codereview.chromium.org/2318933002/

Current chromium/src can build all with is_official_build=true in windows.
This improves build parallelism on windows.

Bug: 634231
Change-Id: Ie16541b56d90718ab01a992b7f4cbc07caebcd22
Reviewed-on: https://chromium-review.googlesource.com/836627Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#525565}

third_party/WebKit/Source/bindings/core/v8/BUILD.gn

@@ -145,8 +145,7 @@ generate_origin_trial_features("bindings_core_origin_trial_features") {
   ]
 }
 
-if (is_win || use_jumbo_build) {
-  # On Windows Official release builds, we try to preserve symbol space.
+if (use_jumbo_build) {
   bindings_core_generated_interface_files =
       [ "$bindings_core_v8_output_dir/V8GeneratedCoreBindings.cpp" ]
 } else {
@@ -173,7 +172,7 @@ group("bindings_core_v8_generated") {
   public_deps = [
     ":bindings_core_impl_generated",
   ]
-  if (is_win || use_jumbo_build) {
+  if (use_jumbo_build) {
     public_deps += [ ":generate_bindings_core_v8_all_interfaces" ]
   } else {
     public_deps += [ ":generate_bindings_core_v8_interfaces" ]