Support DOMStringMap in generators.

lib/dom/scripts/generator.py

Index: lib/dom/scripts/generator.py
diff --git a/lib/dom/scripts/generator.py b/lib/dom/scripts/generator.py
index ff0701590fded44bcf855c76e13dc11ec5eba7bf..6a6ed978961d5bd9da79e46c2ce28dc48b5e742d 100644
--- a/lib/dom/scripts/generator.py
+++ b/lib/dom/scripts/generator.py
@@ -17,6 +17,7 @@ _idl_to_dart_type_conversions = {
     'DOMObject': 'Object',
     'DOMString': 'String',
     'DOMStringList': 'List<String>',
+    'DOMStringMap': 'Map<String, String>',

[sra1, 2012/04/06 18:23:39]

We can't do this.

There is a DOMStringMap type.
In the JavaScript world, element.dataset returns an object that satisfies  (x
instanceof DOMStringMap).
DOMStringMap should *implement* Map<String, String>.

An interface method / getter may returning DOMStringMap may widen to
Map<String,String> but the implementation class (in the frog code) absolutely
must have the correct implementation type.

DOMStringMap is magical - 
element.dataset['foo'] = bar
modifies the element to add a data-foo attribute.

DOMStringList also needs to be handled correctly.
When we access IDBDatabase.objectStoreNames we get a DOMStringList which needs
to implement List<String>
There are two differences:
1. DOMStringList is immutable so no magical behaviour
2. DOMStringList is also an input (e.g. to IDBDatabase.transaction), so this
needs to work:

    mydatabase.transaction(mydatabase.objectStoreNames, ...)

[Anton Muhin, 2012/04/09 09:50:51]

No, we can :)
No, as of now there are none.  As there was no dataset attribute on Element
interface---this line is necessary to make us generate dataset attribute if we
remove DOMStringMap interface as we do now.
No doubt about that.
That's NodeList's level of magic.
No doubt about that as well.
Absolutely, I even already have a todo for that in Dartium code.

     'DOMTimeStamp': 'int',
     'Date': 'Date',
     # Map to num to enable callers to pass in Dart int, rational
@@ -529,13 +530,18 @@ class IDLTypeInfo(object):
     return 'receiver->'
 
   def conversion_includes(self):
-    def NeededDartType(type_name):
+    def NeededDartTypes(type_name):
       match = re.match(r'List<(\w*)>$', type_name)
       if match:
-        return NeededDartType(match.group(1))
-      return type_name
+        return NeededDartTypes(match.group(1))
+      match = re.match(r'Map<(\w*), (\w*)>$', type_name)
+      if match:
+        return NeededDartTypes(match.group(1)) + NeededDartTypes(match.group(2))
+      if IsPrimitiveType(type_name):
+        return []
+      return [type_name]
 
-    return ['"Dart%s.h"' % include for include in [NeededDartType(self.dart_type())] + self._conversion_includes]
+    return ['"Dart%s.h"' % include for include in NeededDartTypes(self.dart_type()) + self._conversion_includes]
 
   def conversion_cast(self, expression):
     if self._conversion_template: