Revert 92668 - Remove more unnecessary ChromeURLRequestContext members.

Revert 92668 - Remove more unnecessary ChromeURLRequestContext members.

ProfileIOData is now always deleted on the IO thread. Replaces a use of ChromeURLRequestContextGetter with a ChromeURLDataManagerBackend getter callback. Also gets rid of ExtensionInfoMap from ChromeURLRequestContext by directly passing it into the places that need it. Gets rid of the HTML5 storage objects from ChromeURLRequestContext too.

Adds a workaround for TranslateManager's Profile::GetDefaultRequestContext() use, since after this refactoring (by not requiring ChromeURLRequestContextGetter for ChromeURLDataManagerBackend), it prevents having to initialize the ChromeURLRequestContextGetter in most tests since they don't actually use it. This means |default_request_context_| doesn't always get initialized in BrowserMain(), which causes TranslateManager to crash on startup since it requires |default_request_context_| to be initialized. So we forcibly initialize |default_request_context_| until TranslateManager stops depending on this.

BUG=89396
TEST=none


Review URL: http://codereview.chromium.org/7282054

TBR=willchan@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=92673