Make SelectionController not to set invalid selection by mouse down

Do not set invalid selection on mouse down

This patch changes |SelectionController| not to set invalid selection by
mouse button down. When processing mouse button down, Blink dispatches
"selectstart" event then updates selection.

Before this patch, Blink attempts to set invalid selection which invalidate by
"selectstart" event handler.

BUG=407791
TEST=LayoutTests/editing/selection/selectstart-event-crash.html

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=200521

[yosin_UTC9, 2015-08-13 09:28:44]

yosin@chromium.org changed reviewers:
+ hajimehoshi@chromium.org

[yosin_UTC9, 2015-08-13 09:29:06]

PTAL

[hajimehoshi, 2015-08-13 09:45:36]

lgtm

> This patch changes |SelectionController| not to se invalid selection by

s/se/see/

https://codereview.chromium.org/1288883002/diff/20001/LayoutTests/editing/sel...
File LayoutTests/editing/selection/selectstart-event-crash.html (right):

https://codereview.chromium.org/1288883002/diff/20001/LayoutTests/editing/sel...
LayoutTests/editing/selection/selectstart-event-crash.html:17:
assert_true(selection.rangeCount == 0);
assert_equals

[yosin_UTC9, 2015-08-13 09:51:35]

Thanks for reviewing!

Committing...

https://codereview.chromium.org/1288883002/diff/20001/LayoutTests/editing/sel...
File LayoutTests/editing/selection/selectstart-event-crash.html (right):

https://codereview.chromium.org/1288883002/diff/20001/LayoutTests/editing/sel...
LayoutTests/editing/selection/selectstart-event-crash.html:17:
assert_true(selection.rangeCount == 0);
On 2015/08/13 09:45:36, hajimehoshi wrote:
> assert_equals

Done.

[yosin_UTC9, 2015-08-13 09:51:38]

The CQ bit was checked by yosin@chromium.org

[yosin_UTC9, 2015-08-13 09:51:38]

The patchset sent to the CQ was uploaded after l-g-t-m from
hajimehoshi@chromium.org
Link to the patchset: https://codereview.chromium.org/1288883002/#ps40001
(title: "2015-08-13T18:48:09")

[commit-bot: I haz the power, 2015-08-13 09:51:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1288883002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1288883002/40001

[commit-bot: I haz the power, 2015-08-13 10:49:14]

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

[commit-bot: I haz the power, 2015-08-13 10:49:14]

Try jobs failed on following builders:
  win_chromium_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[yosin_UTC9, 2015-08-14 01:56:44]

The CQ bit was checked by yosin@chromium.org

[commit-bot: I haz the power, 2015-08-14 01:56:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1288883002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1288883002/40001

[commit-bot: I haz the power, 2015-08-14 03:56:59]

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

[commit-bot: I haz the power, 2015-08-14 03:56:59]

Try jobs failed on following builders:
  win_chromium_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[yosin_UTC9, 2015-08-14 04:56:29]

The CQ bit was checked by yosin@chromium.org

[commit-bot: I haz the power, 2015-08-14 04:56:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1288883002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1288883002/40001

[commit-bot: I haz the power, 2015-08-14 05:59:31]

Committed patchset #3 (id:40001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=200521