override chrome:// URLs via extensions.

chrome/common/extensions/extension.h

Index: chrome/common/extensions/extension.h
diff --git a/chrome/common/extensions/extension.h b/chrome/common/extensions/extension.h
index ab68d60058825c708fcbe98a0e6a3b2d73b7b92c..a84cf4614be0b4c24e1120703892002da84d56e4 100644
--- a/chrome/common/extensions/extension.h
+++ b/chrome/common/extensions/extension.h
@@ -262,6 +262,11 @@ class Extension {
     default_locale_ = default_locale;
   }
 
+  // Chrome URL overrides (see ExtensionOverrideUI).
+  DictionaryValue* GetChromeURLOverrides() const {
+    return chrome_url_overrides_.get();
+  }
+
   // Runtime data:
   // Put dynamic data about the state of a running extension below.
 
@@ -382,6 +387,10 @@ class Extension {
   // Default locale, used for fallback.
   std::string default_locale_;
 
+  // A map of chrome:// hostnames (newtab, downloads, etc.) to Extension URLs
+  // which override the handling of those URLs.
+  scoped_ptr<DictionaryValue> chrome_url_overrides_;
+
   // Runtime data:
 
   // True if the background page is ready.