Turn on warnings for usage of disabled V8 APIs

build/standalone.gypi

Index: build/standalone.gypi
diff --git a/build/standalone.gypi b/build/standalone.gypi
index 186db6e496bc462582a605cb6991d47ca77b39ae..c0eaef419df30e2ff6538aed44e0940d87aa128d 100644
--- a/build/standalone.gypi
+++ b/build/standalone.gypi
@@ -161,6 +161,10 @@
     'ldflags': [
       '-pthread',
     ],
+    'defines': [
+      # Don't use deprecated V8 APIs anywhere.
+      'V8_DEPRECATION_WARNINGS',
+    ],
     'msvs_cygwin_dirs': ['<(DEPTH)/v8/third_party/cygwin'],
     'msvs_configuration_attributes': {
       'OutputDirectory': '<(DEPTH)\\build\\$(ConfigurationName)',
@@ -283,4 +287,4 @@
     # See comment in Chromium's common.gypi for why this is needed.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   }
-}
+}