Pass gfx structs by const ref (gfx::PointF)

Pass gfx structs by const ref (gfx::PointF)

Avoid unneccessary copy of structures gfx::PointF by passing
them by const ref rather than value. Any struct of size > 4 bytes
should be passed by const ref. Passing by ref for these structs
is faster than passing by value, especially when invoking function
has multiple parameters.
Reviewed at https://chromiumcodereview.appspot.com/139233002

BUG=159273
Committed: https://crrev.com/0c9d20046ecd599c511fd7f4ff8e8df83230b03d
Cr-Commit-Position: refs/heads/master@{#327651}

[a.berwal, 2015-04-29 12:14:19]

a.berwal@samsung.com changed reviewers:
+ avi@chromium.org, danakj@chromium.org, jamesr@chromium.org

[a.berwal, 2015-04-29 12:14:19]

PTAL

[Avi (use Gerrit), 2015-04-29 15:19:46]

LGTM

[danakj, 2015-04-29 17:01:03]

LGTM

[a.berwal, 2015-04-30 03:14:31]

The CQ bit was checked by a.berwal@samsung.com

[commit-bot: I haz the power, 2015-04-30 03:14:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1109393002/1

[commit-bot: I haz the power, 2015-04-30 04:10:37]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-30 04:11:33]

Patchset 1 (id:??) landed as
https://crrev.com/0c9d20046ecd599c511fd7f4ff8e8df83230b03d
Cr-Commit-Position: refs/heads/master@{#327651}