drag-and-drop bookmarklet to navigation bar causes whitescreen

[diracdeltas]

Did you search for similar issues before submitting this one?
yes

Describe the issue you encountered:
dragging and dropping a javascript: url to the navigation bar area (not the bookmarks toolbar) causes the browser to whitescreen. demo: open https://jsfiddle.net/r2ftho8k/ and drag the 'click me' link to the navbar.

Expected behavior:
nothing should happen

• Any related issues:
  may be a regression of Dragging a Bookmarklet to the tab-bar area causes the browser to whitescreen #259

[diracdeltas]

the top-level browser location is about:blank so not a security issue afaict

[diracdeltas]

I think loading javascript: does not fire the will-navigate event, so we can't filter out the URL in our will-navigate handler. Probably as an XSS-prevention mechanism, the browser autoredirects to about:blank. I have a quick workaround but would be safer to either add a custom cancelable event in Electron for all webcontent location changes, or fastidiously add drop handlers in the browser window area.

cc @bridiver @bbondy

[bridiver]

will-navigate is explicitly not fired for certain types of navigation. Dragging the link causes a fatal error
[82653:0523/152955:ERROR:atom_bindings.cc(39)] Fatal error in V8: v8::HandleScope::CreateHandle() Cannot create a handle without a HandleScope

[bridiver]

this is temporarily re-opened with 0d4098f and will be closed again by #1917 when it is merged