cc: Fix non root copy request visible rect in HighDPI

cc: Fix non root copy request visible rect in HighDPI

Before while transform clip into layer space, incorrectly used wrong
helper function and applied device scale twice. Create correct helper
function and add unittest.

BUG=622083
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review-Url: https://codereview.chromium.org/2117183002
Cr-Commit-Position: refs/heads/master@{#403782}
(cherry picked from commit 296dd9f02b09445ad5976396a86c00ff3181c253)

Committed: https://chromium.googlesource.com/chromium/src/+/6196d6ec443cd6290a1eff911532d62b52f56d38

[weiliangc, 2016-07-13 20:05:28]

Description was changed from

==========
cc: Fix non root copy request visible rect in HighDPI

Before while transform clip into layer space, incorrectly used wrong
helper function and applied device scale twice. Create correct helper
function and add unittest.

BUG=622083
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review-Url: https://codereview.chromium.org/2117183002
Cr-Commit-Position: refs/heads/master@{#403782}
(cherry picked from commit 296dd9f02b09445ad5976396a86c00ff3181c253)
==========

to

==========
cc: Fix non root copy request visible rect in HighDPI

Before while transform clip into layer space, incorrectly used wrong
helper function and applied device scale twice. Create correct helper
function and add unittest.

BUG=622083
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review-Url: https://codereview.chromium.org/2117183002
Cr-Commit-Position: refs/heads/master@{#403782}
(cherry picked from commit 296dd9f02b09445ad5976396a86c00ff3181c253)

Committed:
https://chromium.googlesource.com/chromium/src/+/6196d6ec443cd6290a1eff911532...
==========

[weiliangc, 2016-07-13 20:05:29]

Committed patchset #1 (id:1) manually as
6196d6ec443cd6290a1eff911532d62b52f56d38.