Fix SessionStorage confusion between RenderViewHostImpl and NavigationController.

Fix SessionStorage confusion between RenderViewHostImpl and NavigationController.

Both RenderViewHostImpl and NavigationController had SessionStorageNamespace*,
and under some circumstances, they pointed to different
SessionStorageNamespaces* which is wrong.

This change makes it so that only NavigationController knows about
SessionStorageNamespace.

For more information, see bug.

BUG=138152
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=213253

[marja, 2013-07-23 13:59:02]

jochen, ajwong, ptal.

This is like https://codereview.chromium.org/18500005 (that one got reverted)
except better. The beef is still that only NavigationController knows about
SessionStorageNamespace, and RenderViewHost asks it via RenderViewHostDelegate.
But this time, no (wrong) "cleanup" regarding the storage partitions.

It's questionable if this is enough to fix the bug (as many places still use
GetDefaultSessionStorageNamespace), but at least this is a sane thing to do.

Pls review:

jochen: everything
ajwong: pls review that the storage partition cleanup is done correctly *this
time* :)

[marja, 2013-07-23 13:59:31]

(cc michaeln again)

[jochen (gone - plz use gerrit), 2013-07-23 14:02:31]

lgtm

[marja, 2013-07-23 19:54:27]

oops, not awong but ajwong. ptal, ajwong.

[awong, 2013-07-23 19:59:35]

LGTM

(fyi, ajwong and awong both work I think)

[commit-bot: I haz the power, 2013-07-23 20:17:08]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/marja@chromium.org/19491004/1

[commit-bot: I haz the power, 2013-07-23 23:02:44]

Change committed as 213253