Fix inspector overlay when use-zoom-for-dsf is enabled.

Fix inspector overlay when use-zoom-for-dsf is enabled.

Inspector overlays were misaligned because the path points were drawing
in window coordinates and needed to be scaled to viewport coordinates.
Should be no change when use-zoom-for-dsf is off.

BUG=622862
Committed: https://crrev.com/6651b97ebd509e97bea8929303738dc20a3ed880
Review-Url: https://codereview.chromium.org/2108803006
Cr-Original-Commit-Position: refs/heads/master@{#404063}
Cr-Commit-Position: refs/heads/master@{#404285}
(cherry picked from commit fca01d88e345fce580cd8acc7245f6cdc89a0c84)

Committed: https://chromium.googlesource.com/chromium/src/+/832b7af69ca7e4d63a86d04f6f6ffc4a4466a1cb

[Bret, 2016-07-11 18:33:39]

Description was changed from

==========
Fix inspector overlay when use-zoom-for-dsf is enabled.

Inspector overlays were misaligned because the path points were drawing
in window coordinates and needed to be scaled to viewport coordinates.
Should be no change when use-zoom-for-dsf is off.

BUG=622862

Committed: https://crrev.com/6651b97ebd509e97bea8929303738dc20a3ed880
Review-Url: https://codereview.chromium.org/2108803006
Cr-Original-Commit-Position: refs/heads/master@{#404063}
Cr-Commit-Position: refs/heads/master@{#404285}
(cherry picked from commit fca01d88e345fce580cd8acc7245f6cdc89a0c84)
==========

to

==========
Fix inspector overlay when use-zoom-for-dsf is enabled.

Inspector overlays were misaligned because the path points were drawing
in window coordinates and needed to be scaled to viewport coordinates.
Should be no change when use-zoom-for-dsf is off.

BUG=622862

Committed: https://crrev.com/6651b97ebd509e97bea8929303738dc20a3ed880
Review-Url: https://codereview.chromium.org/2108803006
Cr-Original-Commit-Position: refs/heads/master@{#404063}
Cr-Commit-Position: refs/heads/master@{#404285}
(cherry picked from commit fca01d88e345fce580cd8acc7245f6cdc89a0c84)

Committed:
https://chromium.googlesource.com/chromium/src/+/832b7af69ca7e4d63a86d04f6f6f...
==========

[Bret, 2016-07-11 18:33:41]

Committed patchset #1 (id:1) manually as
832b7af69ca7e4d63a86d04f6f6ffc4a4466a1cb.