[Telemetry] Fix tab list updating with connected tabs.

[Telemetry] Fix tab list updating with connected tabs.

When you connect to a tab's websocket, Chrome no longer reports a websocketDebuggerUrl. TabListBackend wasn't treating this case correctly, causing its tab list to have "None" tabs, which led to all sorts of fun corruption.


BUG=166243, 174922
TEST=Unit test included. ./run_tests testMultipleTabs

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=182341

[hartmanng, 2013-02-13 23:19:57]

tab_list_backend.py LGTM, could you explain the unit test though? It seems a bit
indirect, would it cause a crash before the fix?

[dtu, 2013-02-13 23:45:41]

I've replaced the unit test with a slightly more straightforward one. Yes, the
key thing is doing a TabList action while having a reference to a Tab previously
caused a crash.

I've also added a second unit test that tests the change to CloseTab(). It
ensures that if the user holds on to a reference to the Tab after the Tab is
closed, it doesn't cause tab list corruption.

[hartmanng, 2013-02-13 23:49:37]

ah thanks, LGTM