DevTools: [Console] fix viewport stick-to-bottom behavior

DevTools: [Console] fix viewport stick-to-bottom behavior

The patch fixes viewport "stick-to-bottom" behavior.

By contract, the client of ViewportControl will change amount of
viewported elements and then call ViewportControl::invalidate, signaling
to update rendered elements.

The patch changes ViewportControl::refresh method so that it doesn't
re-query elements from provider if provider's item count changes.
This corresponds with the API contract.

After that, the stick-to-bottom behavior should be taken in consideration
only for ViewportControl::invalidate calls.

BUG=580381
R=dgozman, pfeldman

Committed: https://crrev.com/e26b3a1a0f2ea3311fb990f6740c3a1d794ba5c4
Cr-Commit-Position: refs/heads/master@{#375107}

[lushnikov, 2016-02-11 01:00:46]

зефд

[dgozman, 2016-02-11 01:22:01]

let's add a test

[lushnikov, 2016-02-11 02:39:18]

here comes the test

[dgozman, 2016-02-11 18:18:50]

lgtm

[lushnikov, 2016-02-11 22:59:40]

The CQ bit was checked by lushnikov@chromium.org

[lushnikov, 2016-02-11 22:59:40]

The patchset sent to the CQ was uploaded after l-g-t-m from dgozman@chromium.org
Link to the patchset: https://codereview.chromium.org/1688053004/#ps40001
(title: " ")

[commit-bot: I haz the power, 2016-02-11 23:04:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1688053004/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1688053004/40001

[commit-bot: I haz the power, 2016-02-12 00:57:56]

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

[commit-bot: I haz the power, 2016-02-12 00:57:57]

Try jobs failed on following builders:
  mac_chromium_rel_ng on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[lushnikov, 2016-02-12 02:42:02]

The CQ bit was checked by lushnikov@chromium.org

[commit-bot: I haz the power, 2016-02-12 02:43:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1688053004/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1688053004/40001

[commit-bot: I haz the power, 2016-02-12 03:18:32]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-02-16 22:41:14]

Description was changed from

==========
DevTools: [Console] fix viewport stick-to-bottom behavior

The patch fixes viewport "stick-to-bottom" behavior.

By contract, the client of ViewportControl will change amount of
viewported elements and then call ViewportControl::invalidate, signaling
to update rendered elements.

The patch changes ViewportControl::refresh method so that it doesn't
re-query elements from provider if provider's item count changes.
This corresponds with the API contract.

After that, the stick-to-bottom behavior should be taken in consideration
only for ViewportControl::invalidate calls.

BUG=580381
R=dgozman, pfeldman
==========

to

==========
DevTools: [Console] fix viewport stick-to-bottom behavior

The patch fixes viewport "stick-to-bottom" behavior.

By contract, the client of ViewportControl will change amount of
viewported elements and then call ViewportControl::invalidate, signaling
to update rendered elements.

The patch changes ViewportControl::refresh method so that it doesn't
re-query elements from provider if provider's item count changes.
This corresponds with the API contract.

After that, the stick-to-bottom behavior should be taken in consideration
only for ViewportControl::invalidate calls.

BUG=580381
R=dgozman, pfeldman

Committed: https://crrev.com/e26b3a1a0f2ea3311fb990f6740c3a1d794ba5c4
Cr-Commit-Position: refs/heads/master@{#375107}
==========

[commit-bot: I haz the power, 2016-02-16 22:41:15]

Patchset 3 (id:??) landed as
https://crrev.com/e26b3a1a0f2ea3311fb990f6740c3a1d794ba5c4
Cr-Commit-Position: refs/heads/master@{#375107}