Rename HostZoomMap::GetForBrowserContext() to GetDefaultForBrowserContext().

Rename HostZoomMap::GetForBrowserContext() to GetDefaultForBrowserContext().

HostZoomMap will be moving from BrowserContext to StoragePartition soon
as part of fixing this bug. Many sites will still want to access the
default HostZoomMap for a BrowserContext, so we will rename this
function in order to be clear about that.

BUG=335317
Committed: https://crrev.com/f9b6ec8dbfbeb21efadd970ccf11889ef580a751
Cr-Commit-Position: refs/heads/master@{#292147}

[wjmaclean, 2014-08-26 17:35:23]

wjmaclean@chromium.org changed reviewers:
+ jam@chromium.org

[wjmaclean, 2014-08-26 17:35:23]

jam@ - This is a very simple function re-naming CL in preparation for migrating
HostZoomMaps into StoragePartitions.

Could you please look at the HostZoomMap changes?

[jam, 2014-08-27 03:38:19]

lgtm

[wjmaclean, 2014-08-27 12:46:15]

The CQ bit was checked by wjmaclean@chromium.org

[commit-bot: I haz the power, 2014-08-27 12:46:33]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/wjmaclean@chromium.org/506073002/1

[commit-bot: I haz the power, 2014-08-27 14:02:26]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_chromium_compile_dbg on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_comp...)

[commit-bot: I haz the power, 2014-08-27 14:33:33]

Committed patchset #1 (1) as eda34589a11f662b863890fe3dc6f1a63d652338

[commit-bot: I haz the power, 2014-09-10 02:51:30]

Patchset 1 (id:??) landed as
https://crrev.com/f9b6ec8dbfbeb21efadd970ccf11889ef580a751
Cr-Commit-Position: refs/heads/master@{#292147}