Add DCHECK to MaskedViewTargeter::GetHitTestMask() overrides

Add DCHECK to MaskedViewTargeter::GetHitTestMask() overrides

Add DCHECK_EQ(view, masked_view()) to the overrides of
MaskedViewTargeter::GetHitTestMask(). This is to ensure
the function is only called with |view| corresponding
to the view on which the targeter is installed.

This is nice to have because GetHitTestMask()
is called directly from a few places such as
overrides of View::GetHitTestMask() and (soon)
from within TabCloseButtonTargeter; see issue
377557.

BUG=377527
TEST=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=274852

[tdanderson, 2014-06-02 23:14:25]

Sadrul, can you please take a look?

[sadrul, 2014-06-03 16:37:01]

This change implies that these Views (i.e. new-tab button, mic-button) either
won't have any children, or each of its child Views will have its own targeter,
right?

https://codereview.chromium.org/308003019/diff/1/chrome/browser/ui/views/tabs...
File chrome/browser/ui/views/tabs/tab_strip.cc (right):

https://codereview.chromium.org/308003019/diff/1/chrome/browser/ui/views/tabs...
chrome/browser/ui/views/tabs/tab_strip.cc:433: DCHECK(view == masked_view());
Use DCHECK_EQ

[tdanderson, 2014-06-03 18:22:54]

I don't believe this will cause problems if there is a view with a
MaskedViewTargeter installed that has a child view without its own targeter
installed. This is because of the way
MaskedViewTargeter::EventLocationInsideBounds() is implemented: if view !=
masked_view_, then GetHitTestMask() is not called and the default implementation
in ViewTargeter is used instead.

https://codereview.chromium.org/308003019/diff/1/chrome/browser/ui/views/tabs...
File chrome/browser/ui/views/tabs/tab_strip.cc (right):

https://codereview.chromium.org/308003019/diff/1/chrome/browser/ui/views/tabs...
chrome/browser/ui/views/tabs/tab_strip.cc:433: DCHECK(view == masked_view());
On 2014/06/03 16:37:01, sadrul wrote:
> Use DCHECK_EQ

Done.

[sadrul, 2014-06-03 18:28:41]

lgtm

[tdanderson, 2014-06-03 19:21:18]

Adding sky@ (chrome/) and xiyuan@ (ui/app_list) for OWNERS review.

[xiyuan, 2014-06-03 19:44:22]

ui/app_list LGTM

[sky, 2014-06-03 20:16:01]

LGTM

[tdanderson, 2014-06-04 15:58:18]

The CQ bit was checked by tdanderson@chromium.org

[commit-bot: I haz the power, 2014-06-04 15:59:46]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tdanderson@chromium.org/308003019/20001

[commit-bot: I haz the power, 2014-06-04 17:09:59]

Change committed as 274852