Split out libplatform into a separate libary

build/features.gypi

Index: build/features.gypi
diff --git a/build/features.gypi b/build/features.gypi
index e808788657f2bf967bbf1fde209cf604c4295fc0..7ce66e4c98e87cb4c8a4a9a6c404eea1b435bf36 100644
--- a/build/features.gypi
+++ b/build/features.gypi
@@ -59,9 +59,6 @@
     # Enable compiler warnings when using V8_DEPRECATED apis.
     'v8_deprecation_warnings%': 0,
 
-    # Use the v8 provided v8::Platform implementation.
-    'v8_use_default_platform%': 1,
-
     # Use external files for startup data blobs:
     # the JS builtins sources and the start snapshot.
     'v8_use_external_startup_data%': 0,
@@ -92,9 +89,6 @@
       ['v8_enable_i18n_support==1', {
         'defines': ['V8_I18N_SUPPORT',],
       }],
-      ['v8_use_default_platform==1', {
-        'defines': ['V8_USE_DEFAULT_PLATFORM',],
-      }],
       ['v8_compress_startup_data=="bz2"', {
         'defines': ['COMPRESS_STARTUP_DATA_BZ2',],
       }],