Implement support for <extensionoptions> embedding in WebUI

chrome/browser/extensions/api/guest_view/guest_view_internal_api.cc

Index: chrome/browser/extensions/api/guest_view/guest_view_internal_api.cc
diff --git a/chrome/browser/extensions/api/guest_view/guest_view_internal_api.cc b/chrome/browser/extensions/api/guest_view/guest_view_internal_api.cc
index 7765d9b428effee7c37bdf42fb4f0ed98ce87f49..39f31d45788a94855b546e39564f2ab0d411f31e 100644
--- a/chrome/browser/extensions/api/guest_view/guest_view_internal_api.cc
+++ b/chrome/browser/extensions/api/guest_view/guest_view_internal_api.cc
@@ -33,8 +33,17 @@ bool GuestViewInternalCreateGuestFunction::RunAsync() {
   GuestViewManager::WebContentsCreatedCallback callback =
       base::Bind(&GuestViewInternalCreateGuestFunction::CreateGuestCallback,
                  this);
+
+  // If this the guest is an <extensionoptions> to be embedded in a WebUI, then
+  // there is no extension, and extension() will be null. Use an empty string

[not at google - send to devlin, 2014/08/07 23:06:02]

this shouldn't be necessary after https://codereview.chromium.org/426593007/
goes in

[ericzeng, 2014/08/08 00:23:46]

I'm not sure if that's the case. ExtensionFunction::extension_id() gets the id
by calling extension_->id(), but extension_ will be NULL if I embed my guest
view in WebUI, which causes it to crash in here. Did you make any modifications
to ExtensionFunction elsewhere?

[not at google - send to devlin, 2014/08/08 14:08:15]

ah you're right, my bad sorry.

1 last nit: the last sentence isn't needed.

+  // instead.
+  std::string embedder_extension_id = "";

[Fady Samuel, 2014/08/07 23:09:29]

no need for initializer.

[ericzeng, 2014/08/08 00:23:46]

Done.

+  if (extension()) {

[Fady Samuel, 2014/08/07 23:09:29]

No need for braces.

[ericzeng, 2014/08/08 00:23:46]

Done.

+    embedder_extension_id = extension_id();
+  }
+
   guest_view_manager->CreateGuest(view_type,
-                                  extension_id(),
+                                  embedder_extension_id,
                                   render_view_host()->GetProcess()->GetID(),
                                   *create_params,
                                   callback);