Fix GN build on Linux ChromiumOS

Fix GN build on Linux ChromiumOS

This is a fix for Linux ChromiumOS GN build:
http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20GN/builds/5292

"view_event_test_platform_part_ash.cc" is not in 'sources'.

BUG=n/a
TEST=build
TBR=brettw@chromium.org
NOTRY=true

Committed: https://crrev.com/45dcea9064c39161b112b1810e78de13b044e991
Cr-Commit-Position: refs/heads/master@{#310050}

[nhiroki, 2015-01-06 04:17:01]

nhiroki@chromium.org changed reviewers:
+ brettw@chromium.org

[nhiroki, 2015-01-06 04:29:39]

The CQ bit was checked by nhiroki@chromium.org

[commit-bot: I haz the power, 2015-01-06 04:29:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/816393003/1

[commit-bot: I haz the power, 2015-01-06 04:30:38]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-06 04:31:38]

Patchset 1 (id:??) landed as
https://crrev.com/45dcea9064c39161b112b1810e78de13b044e991
Cr-Commit-Position: refs/heads/master@{#310050}

[nhiroki, 2015-01-06 04:47:42]

Hmmm... this leads a compile failure on the bot. Let me revert this and the
original patch:
http://build.chromium.org/p/chromium.chromiumos/buildstatus?builder=Linux%20C...

[nhiroki, 2015-01-06 04:48:52]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/794053007/ by nhiroki@chromium.org.

The reason for reverting is: This broke the GN compile on chromeos:
http://build.chromium.org/p/chromium.chromiumos/buildstatus?builder=Linux%20C....