[heap] Port concurrent marking flag to GYP.

This enables concurrent marking for x86 and x64 on GYP builds.

Bug: chromium:694255
Change-Id: I371b38e72ce0e8f7ad5b0eed4e29b223b9ed1cf4
Reviewed-on: https://chromium-review.googlesource.com/628836
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47551}

Makefile

@@ -63,6 +63,10 @@ endif
 ifeq ($(tracemaps), on)
   GYPFLAGS += -Dv8_trace_maps=1
 endif
+# concurrentmarking=on
+ifeq ($(concurrentmarking), on)
+  GYPFLAGS += -Dv8_enable_concurrent_marking=1
+endif
 # backtrace=off
 ifeq ($(backtrace), off)
   GYPFLAGS += -Dv8_enable_backtrace=0

gypfiles/features.gypi

@@ -29,6 +29,10 @@
 
 {
   'variables': {
+    'variables': {
+      'v8_target_arch%': '<(target_arch)',
+    },
+
     'v8_enable_disassembler%': 0,
 
     'v8_promise_internal_field_count%': 0,
@@ -76,6 +80,15 @@
 
     # Temporary flag to allow embedders to update their microtasks scopes.
     'v8_check_microtasks_scopes_consistency%': 'false',
+
+    # Enable concurrent marking.
+    'conditions': [
+      ['v8_target_arch=="x64" or v8_target_arch=="ia32"', {
+        'v8_enable_concurrent_marking%': 1,
+      },{
+        'v8_enable_concurrent_marking%': 0,
+      }]
+    ],
   },
   'target_defaults': {
     'conditions': [
@@ -124,6 +137,9 @@
       ['v8_check_microtasks_scopes_consistency=="true"', {
         'defines': ['V8_CHECK_MICROTASKS_SCOPES_CONSISTENCY',],
       }],
+      ['v8_enable_concurrent_marking==1', {
+        'defines': ['V8_CONCURRENT_MARKING',],
+      }],
     ],  # conditions
     'configurations': {
       'DebugBaseCommon': {