Fix cert-handler

[jegger]

CEFBrowser.certificate_error_handler;
TypeError: unbound method must be called with CEFBrowser instance as first argument (got int instance instead)

Resolved the problem. Others arise:

• We also need a callback (e.g. if we want to ask the user to accept the certificate)
• We need to investigate, whether CEFPython could give the browser instance with OnCertificateError

[cztomczak]

@rtsh The browser parameter is missing in upstream CEF. It was added only recently in branch 2272 revision 2029: https://code.google.com/p/chromiumembedded/issues/detail?id=1530

@CzarekTomczak I wonder if it would be possible to pass the browser instance to the ClientHandler here: https://code.google.com/p/cefpython/source/browse/cefpython/cefpython.pyx#392
So the ClientHandler would know which browser is associated with it. Then we could already implement this before having the fix in upstream CEF.

[cztomczak]

@rtsh The problem is that we can assign browser instance to client handler only after browser was created. Currently only synchronous browser creation is available. So it's probably not possible to have the browser parameter available during initial browser navigation. However to be sure about that one would need to run tests. You could edit ClientHandler C++ code and add browserIdentifier_ property. Set it in cefpython.pyx you refered to. And then pass it to and check in RequestHandler_OnCertificateError() whether GetPyBrowserById() returns not empty value. Even if this doesn't work, it can still work assuming that the initial url during browser creation is guaranteed to not have a certificate error (about:blank or data:text/html;base64, for example). Browser id would be available for all subsequent browser navigations.

[cztomczak]

In CEF 51 the browser object is now passed to OnCertificateError - but it needs updating cefpython bindings to expose it to python.