Introduce a v8::Platform class that bundles embedder callbacks

build/features.gypi

Index: build/features.gypi
diff --git a/build/features.gypi b/build/features.gypi
index 08ea11ae9b972595e5c931bc96e1dc6913e46f5f..85b8a38465cc3203233c1fa809c0a108280f711c 100644
--- a/build/features.gypi
+++ b/build/features.gypi
@@ -58,6 +58,9 @@
 
     # Enable compiler warnings when using V8_DEPRECATED apis.
     'v8_deprecation_warnings%': 0,
+
+    # Use the v8 provided v8::Platform implementation.
+    'v8_use_default_platform%': 1,

[Benedikt Meurer, 2013/11/18 15:34:44]

Do we really need this option here? Couldn't we just always include our default
implementation, and in V8::Initialize just check whether g_platform is NULL, and
if so, automagically use the default implementation?

[jochen (gone - plz use gerrit), 2013/11/18 16:27:56]

The default implementation will have to provide e.g. a thread pool, so it's a
non-trivial amount of code which I'd like to avoid including if possible.

Also, V8::Initialize just picking a default implementation is too much magic
IMO. It would lead to unexpected results if we e.g. add a new process in chrome
and forget to set the platform there.

[Benedikt Meurer, 2013/11/19 06:57:15]

Hm, so the default implementation is not used by Chrome? What worries me is that
we may then run into trouble with reproducing Chrome behavior in d8. We'll have
to regularily sync the default implementation with Chrome, which is certainly
not what we want. Can we do better here?

   },
   'target_defaults': {
     'conditions': [
@@ -85,6 +88,9 @@
       ['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',