Move nav_entry_id from RenderViewHost to RenderFrameHost.

Move nav_entry_id from RenderViewHost to RenderFrameHost.

We update this value for every current RFH in the FrameTree on each new
NavigationEntry commit.  This allows us to track the latest entry that
is relevant for each RFH, which is where UpdateTitle and UpdateState
messages should apply.

BUG=545219, 369661
TEST=No visible behavior change yet; will enable per-frame UpdateState.

Committed: https://crrev.com/03b4800d12e115a95c5f0ee21c8f7ba3609dbcd3
Cr-Commit-Position: refs/heads/master@{#357690}

[Charlie Reis, 2015-11-03 19:09:29]

Patchset #1 (id:1) has been deleted

[Charlie Reis, 2015-11-03 20:11:53]

creis@chromium.org changed reviewers:
+ avi@chromium.org

[Charlie Reis, 2015-11-03 20:11:54]

Avi, can you take a look?  This unblocks the UpdateState refactor for OOPIFs
(https://codereview.chromium.org/1425303002/), since subframe UpdateStates were
going to the wrong entry with the RVH-based approach.

[Charlie Reis, 2015-11-03 21:02:19]

The CQ bit was checked by creis@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-11-03 21:06:10]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1425293006/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1425293006/20001

[commit-bot: I haz the power, 2015-11-03 21:13:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-11-03 21:13:49]

Dry run: This issue passed the CQ dry run.

[Avi (use Gerrit), 2015-11-04 00:29:12]

lgtm

Woot!

[Charlie Reis, 2015-11-04 00:29:43]

The CQ bit was checked by creis@chromium.org

[Charlie Reis, 2015-11-04 00:33:44]

The CQ bit was unchecked by creis@chromium.org

[Charlie Reis, 2015-11-04 00:33:47]

The CQ bit was checked by creis@chromium.org

[commit-bot: I haz the power, 2015-11-04 00:35:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1425293006/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1425293006/20001

[commit-bot: I haz the power, 2015-11-04 00:55:03]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2015-11-04 00:56:00]

Patchset 1 (id:??) landed as
https://crrev.com/03b4800d12e115a95c5f0ee21c8f7ba3609dbcd3
Cr-Commit-Position: refs/heads/master@{#357690}