Mac: Fix for janky tab dragging/reordering.

Mac: Fix for janky tab dragging/reordering.

-[TabView drawRect:] was called repeatedly to unnecessarily update the glow
that is not changing or should not have changed.

1. Selected tabs don't have glow, so don't redraw on mouseMoved.

2. When dragging an unselected tab, the mouse point relative to the tab view
does not change, so no need to redraw the glow.

3. When a dragged unselected tab slides behind another tab, let the dragged tab
keep the glow instead of the tab in front of it (this is a behavior change).
I think this is the more correct behavior, and we never have to redraw tabs
while dragging.

BUG=452925
Committed: https://crrev.com/2dad4dfbdd6fbc846f09766a263739ea6f3439ed
Cr-Commit-Position: refs/heads/master@{#313734}

[Andre, 2015-01-28 22:52:40]

Patchset #1 (id:1) has been deleted

[Andre, 2015-01-28 23:40:34]

andresantoso@chromium.org changed reviewers:
+ rsesek@chromium.org

[Andre, 2015-01-28 23:40:35]

Robert, please review.

[Robert Sesek, 2015-01-29 16:13:06]

LGTM

https://codereview.chromium.org/882193003/diff/20001/chrome/browser/ui/cocoa/...
File chrome/browser/ui/cocoa/tabs/tab_strip_drag_controller.h (right):

https://codereview.chromium.org/882193003/diff/20001/chrome/browser/ui/cocoa/...
chrome/browser/ui/cocoa/tabs/tab_strip_drag_controller.h:65: // The tab being
dragged, or nil if not dragging a tab.
nit: Should come before init.

[Andre, 2015-01-29 17:30:43]

Patchset #2 (id:40001) has been deleted

[Andre, 2015-01-29 17:31:53]

https://codereview.chromium.org/882193003/diff/20001/chrome/browser/ui/cocoa/...
File chrome/browser/ui/cocoa/tabs/tab_strip_drag_controller.h (right):

https://codereview.chromium.org/882193003/diff/20001/chrome/browser/ui/cocoa/...
chrome/browser/ui/cocoa/tabs/tab_strip_drag_controller.h:65: // The tab being
dragged, or nil if not dragging a tab.
On 2015/01/29 16:13:06, Robert Sesek wrote:
> nit: Should come before init.

Done.

[Andre, 2015-01-29 17:31:59]

The CQ bit was checked by andresantoso@chromium.org

[commit-bot: I haz the power, 2015-01-29 17:33:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/882193003/60001

[commit-bot: I haz the power, 2015-01-29 18:07:50]

Committed patchset #2 (id:60001)

[commit-bot: I haz the power, 2015-01-29 18:08:50]

Patchset 2 (id:??) landed as
https://crrev.com/2dad4dfbdd6fbc846f09766a263739ea6f3439ed
Cr-Commit-Position: refs/heads/master@{#313734}