Address ExtensionApiTest.Tabs flakiness

Address ExtensionApiTest.Tabs flakiness

This addresses two problems. (1) relativeUrlTabsUpdate could fail because it was depending on testTabId getting set from relativeUrlTabsCreate, which may have happened out of order. I have refactored the callback blocking so additional blocks can be created with chrome.test.callbackAdded().

(2) tabs.update({url:}) is still failing intermitantly. This changes addeds valid html files in the extension which can be navitation targets (previously, non-existent urls had been used), in the hopes that the random failures had to do with load errors.

BUG=20828
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=26258

[asargent_no_longer_on_chrome, 2009-09-15 19:16:10]

LGTM

[Erik does not do reviews, 2009-09-15 19:44:35]

LGTM