Enable Shadow DOM and scoped stylesheet for extensions and Web UI.

chrome/renderer/chrome_render_view_observer.cc

Index: chrome/renderer/chrome_render_view_observer.cc
diff --git a/chrome/renderer/chrome_render_view_observer.cc b/chrome/renderer/chrome_render_view_observer.cc
index 03658b5c08c3e8220956be20e09e5957f485a1ae..f54caa277e37cf984376557eddcdd881825a739c 100644
--- a/chrome/renderer/chrome_render_view_observer.cc
+++ b/chrome/renderer/chrome_render_view_observer.cc
@@ -58,6 +58,7 @@
 using WebKit::WebAccessibilityObject;
 using WebKit::WebCString;
 using WebKit::WebDataSource;
+using WebKit::WebDocument;
 using WebKit::WebFrame;
 using WebKit::WebIconURL;
 using WebKit::WebRect;
@@ -482,6 +483,32 @@ bool ChromeRenderViewObserver::allowWriteToClipboard(WebFrame* frame,
   return allowed;
 }
 
+bool ChromeRenderViewObserver::IsExperimentalWebFeatureAllowed(
+    const WebDocument& document) {
+  // Experimental Web API is enabled when
+  // - The specific API is allowed from command line flag, or
+  // - If the document is running extensions or apps which
+  //   has the "experimental" permission, or
+  // - The document is running Web UI.
+  WebSecurityOrigin origin = document.securityOrigin();
+  if (EqualsASCII(origin.protocol(), chrome::kChromeUIScheme))
+    return true;
+  const extensions::Extension* extension =
+      extension_dispatcher_->extensions()->GetExtensionOrAppByURL(
+          ExtensionURLInfo(origin, document.url()));

[Mihai Parparita -not on Chrome, 2012/06/20 19:47:01]

This doesn't seem to quite work. For windows created with window.open (or
chrome.appWindow.create) initially document.url is set to null (and then later
it gets updated). The security origin always has the right extension ID though.

+  if (!extension)
+    return false;
+  return (extension_dispatcher_->IsExtensionActive(extension->id()) &&
+          extension->HasAPIPermission(ExtensionAPIPermission::kExperimental));
+}
+
+bool ChromeRenderViewObserver::allowWebComponents(const WebDocument& document,
+                                                  bool defaultValue) {
+  if (defaultValue)
+    return true;
+  return IsExperimentalWebFeatureAllowed(document);
+}
+
 static void SendInsecureContentSignal(int signal) {
   UMA_HISTOGRAM_ENUMERATION("SSL.InsecureContent", signal,
                             INSECURE_CONTENT_NUM_EVENTS);