Modify blink type map to finalize lazily

tools/dom/templates/html/dartium/_blink_dartium.darttemplate

Index: tools/dom/templates/html/dartium/_blink_dartium.darttemplate
diff --git a/tools/dom/templates/html/dartium/_blink_dartium.darttemplate b/tools/dom/templates/html/dartium/_blink_dartium.darttemplate
index 36c722ba8b82c20830b41b65fb61c40843b04930..d68930f885987921ec191dcc535b4acf1a48962f 100644
--- a/tools/dom/templates/html/dartium/_blink_dartium.darttemplate
+++ b/tools/dom/templates/html/dartium/_blink_dartium.darttemplate
@@ -45,16 +45,16 @@ $!GENERATED_DART_FILES
 Type _getType(String key) {
   // TODO(vsm): Add Cross Frame and JS types here as well.
   if (htmlBlinkMap.containsKey(key))
-    return htmlBlinkMap[key];
+    return htmlBlinkMap[key]();
   if (indexed_dbBlinkMap.containsKey(key))
-    return indexed_dbBlinkMap[key];
+    return indexed_dbBlinkMap[key]();
   if (web_audioBlinkMap.containsKey(key))
-    return web_audioBlinkMap[key];
+    return web_audioBlinkMap[key]();
   if (web_glBlinkMap.containsKey(key))
-    return web_glBlinkMap[key];
+    return web_glBlinkMap[key]();
   if (web_sqlBlinkMap.containsKey(key))
-    return web_sqlBlinkMap[key];
+    return web_sqlBlinkMap[key]();
   if (svgBlinkMap.containsKey(key))
-    return svgBlinkMap[key];
+    return svgBlinkMap[key]();
   return null;
 }