Adds web::NavigationItem.

Adds web::NavigationItem.

This is the web/ analogue of content's NavigationEntry, intended
for use on iOS because iOS cannot depend on content.
NavigationItem captures all the data required to recreate a
browsing state, such as URL, title, and transition type.

BUG=422033
TEST=None

Committed: https://crrev.com/cce127badb2d4150e8458921e393721c80b23981
Cr-Commit-Position: refs/heads/master@{#299093}

[rohitrao (ping after 24h), 2014-10-09 20:26:19]

rohitrao@chromium.org changed reviewers:
+ sky@chromium.org, stuartmorgan@chromium.org

[rohitrao (ping after 24h), 2014-10-09 20:26:20]

+Scott to approve the ios/web -> ui dependency.

+Stuart for the changes in ios/web.  This is an exact copy of the current
internal navigation_item.h file.  I'll make further changes after this CL lands.

[stuartmorgan, 2014-10-09 20:39:35]

LGTM, but could you flesh out the CL description a bit with some context for
people who aren't you and me? :)

https://codereview.chromium.org/647543002/diff/1/ios/web/public/navigation_it...
File ios/web/public/navigation_item.h (right):

https://codereview.chromium.org/647543002/diff/1/ios/web/public/navigation_it...
ios/web/public/navigation_item.h:35: virtual const base::string16& GetTitle()
const = 0;
Looks like we're missing a string16.h include, and relying on it to be already
included when this header is. Could you fix that while you're here?

[rohitrao (ping after 24h), 2014-10-09 20:52:53]

https://codereview.chromium.org/647543002/diff/1/ios/web/public/navigation_it...
File ios/web/public/navigation_item.h (right):

https://codereview.chromium.org/647543002/diff/1/ios/web/public/navigation_it...
ios/web/public/navigation_item.h:35: virtual const base::string16& GetTitle()
const = 0;
On 2014/10/09 20:39:35, stuartmorgan wrote:
> Looks like we're missing a string16.h include, and relying on it to be already
> included when this header is. Could you fix that while you're here?

Done.

[sky, 2014-10-10 02:39:40]

LGTM

[rohitrao (ping after 24h), 2014-10-10 11:45:10]

The CQ bit was checked by rohitrao@chromium.org

[commit-bot: I haz the power, 2014-10-10 11:45:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/647543002/150001

[commit-bot: I haz the power, 2014-10-10 11:48:35]

Committed patchset #2 (id:150001)

[commit-bot: I haz the power, 2014-10-10 11:49:38]

Patchset 2 (id:??) landed as
https://crrev.com/cce127badb2d4150e8458921e393721c80b23981
Cr-Commit-Position: refs/heads/master@{#299093}