Add the scheme chrome-distiller:// and hook up data source.

content/public/browser/content_browser_client.h

Index: content/public/browser/content_browser_client.h
diff --git a/content/public/browser/content_browser_client.h b/content/public/browser/content_browser_client.h
index 0e2e2a36c730460957c816ade9a7697ea679f939..56f6150d9b5f19da6824320fe89d41913e198eca 100644
--- a/content/public/browser/content_browser_client.h
+++ b/content/public/browser/content_browser_client.h
@@ -185,7 +185,8 @@ class CONTENT_EXPORT ContentBrowserClient {
   // Returns a list additional WebUI schemes, if any.  These additional schemes
   // act as aliases to the chrome: scheme.  The additional schemes may or may
   // not serve specific WebUI pages depending on the particular URLDataSource
-  // and its override of URLDataSource::ShouldServiceRequest.
+  // and its override of URLDataSource::ShouldServiceRequest. For all schemes
+  // returned here, view-source is allowed.
   virtual void GetAdditionalWebUISchemes(
       std::vector<std::string>* additional_schemes) {}