Don't paint a border after the last frame on any axis in a frameset

Don't paint a border after the last frame on any axis in a frameset

A border would be painted after the last frame on any axis in a frameset.
This border would usually not be visible since it was clipped out by
the view (or a frame, if in a nested frameset).
Also hoist the check for non-zero border thickness, since if it's zero
the loops won't do anything useful.

BUG=496322
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196600

[fs, 2015-06-05 13:21:04]

fs@opera.com changed reviewers:
+ chrishtr@chromium.org, pdr@chromium.org

[chrishtr, 2015-06-05 18:57:27]

https://codereview.chromium.org/1155093004/diff/1/Source/core/paint/FrameSetP...
File Source/core/paint/FrameSetPainter.cpp (right):

https://codereview.chromium.org/1155093004/diff/1/Source/core/paint/FrameSetP...
Source/core/paint/FrameSetPainter.cpp:68: return index + 1 < axis.m_sizes.size()
&& axis.m_allowBorder[index + 1];
Why index + 1 < axis.m_sizes.size() and not index < .m_sizes.size() ?

[fs, 2015-06-05 19:18:47]

https://codereview.chromium.org/1155093004/diff/1/Source/core/paint/FrameSetP...
File Source/core/paint/FrameSetPainter.cpp (right):

https://codereview.chromium.org/1155093004/diff/1/Source/core/paint/FrameSetP...
Source/core/paint/FrameSetPainter.cpp:68: return index + 1 < axis.m_sizes.size()
&& axis.m_allowBorder[index + 1];
On 2015/06/05 18:57:27, chrishtr wrote:
> Why index + 1 < axis.m_sizes.size() and not index < .m_sizes.size() ?

index is in [0, size()-1], so the latter will always be true. Essentially reject
the last index. An equivalent expression would be:

index < axis.m_sizes.size() - 1 (or even "index != axis.m_sizes.size() - 1" if
one allows oneself)

Maybe that is more clear? (Didn't fancy the subtraction very much myself.)

[chrishtr, 2015-06-05 19:42:41]

The CQ bit was checked by chrishtr@chromium.org

[chrishtr, 2015-06-05 19:42:41]

lgtm

[commit-bot: I haz the power, 2015-06-05 19:42:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1155093004/1

[commit-bot: I haz the power, 2015-06-05 19:46:44]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196600