Add forEach() to CSSVariablesMap

Source/bindings/derived_sources.gyp

Index: Source/bindings/derived_sources.gyp
diff --git a/Source/bindings/derived_sources.gyp b/Source/bindings/derived_sources.gyp
index d0535478b39baa5f8d3459104fc0feb7b8622c52..96b4eb58cd7fd56627ab89e6b2cbd6c653856461 100644
--- a/Source/bindings/derived_sources.gyp
+++ b/Source/bindings/derived_sources.gyp
@@ -56,10 +56,10 @@
         '<@(python_webcore_test_support_idl_files)',
     ],
     'code_generator_template_files': [

[Nils Barth (inactive), 2013/08/06 05:45:18]

You're adding a .tmpl extension to the template files.
I think it's better to leave these files as is.

While I understand the motivation, AFAICT Jinja templates
generally use the usual extension:
"A template is simply a text file. It can generate any text-based format (HTML,
XML, CSV, LaTeX, etc.). It doesn’t have a specific extension, .html or .xml are
just fine."
http://jinja.pocoo.org/docs/templates/

If you want syntax highlighting (which is going to be tricky),
there is some code here:
http://jinja.pocoo.org/docs/integration/
...but it looks like we'll have to wrap our own if we want
C++ and Jinja.

-        'templates/callback_interface.cpp',
-        'templates/callback_interface.h',
-        'templates/interface.cpp',
-        'templates/interface.h',
+        'templates/callback_interface.cpp.tmpl',
+        'templates/callback_interface.h.tmpl',
+        'templates/interface.cpp.tmpl',
+        'templates/interface.h.tmpl',
     ],
 
     'bindings_output_dir': '<(SHARED_INTERMEDIATE_DIR)/blink/bindings',