Fix the Windows implementation of EventGenerator::PressKey().

Fix the Windows implementation of EventGenerator::PressKey().

On Windows, we have to explicitly overwrite Event::flags_ since the flags are not determined by a MSG object but by GetKeyState() Win32 API. This CL is necessary for https://chromiumcodereview.appspot.com/9228013/.

BUG=None
TEST=try

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=118414

[Yusuke Sato, 2012-01-19 23:06:55]

Ben, could you review this?

[Ben Goodger (Google), 2012-01-19 23:12:04]

lgtm

[commit-bot: I haz the power, 2012-01-19 23:19:20]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/yusukes@chromium.org/9241007/6002

[commit-bot: I haz the power, 2012-01-20 03:08:15]

Try job failure for 9241007-6002 (retry) (retry) (retry) on mac_rel for step
"browser_tests".
It's a second try, previously, step "browser_tests" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_rel&nu...

[commit-bot: I haz the power, 2012-01-20 03:20:07]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/yusukes@chromium.org/9241007/6002

[commit-bot: I haz the power, 2012-01-20 05:16:14]

Try job failure for 9241007-6002 (retry) on mac_rel for step "browser_tests".
It's a second try, previously, step "browser_tests" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_rel&nu...