Remove dwm function because it is going away in windows 8.1

Remove dwm function because it is going away in windows 8.1

I am guessing that this does nothing perf-wise, certainly
resize wise I don't observe any improvement wrt to not
having it.

On the even more speculative angle (pun intended)
it might be interfering with flip_ex present experiments.

TBR=jam
TEST=none
BUG=224764
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=212308

[cpu_(ooo_6.6-7.5), 2013-07-12 23:05:05]

do we need Nat to opinionate in this review?

[cpu_(ooo_6.6-7.5), 2013-07-14 19:30:18]

also it seems there is a test failing

GpuTabTest.testScreenshot: 
Traceback (most recent call last):
File
"E:\b\build\slave\win\build\src\tools\telemetry\telemetry\core\tab_unittest.py",
line 77, in testScreenshot
0, 255, 0, tolerance=2)
File
"E:\b\build\slave\win\build\src\tools\telemetry\telemetry\core\chrome\png_bitmap.py",
line 37, in AssertIsRGB
assert self.IsEqual(PngColor(r, g, b), tolerance)
AssertionError

[apatrick_chromium, 2013-07-15 20:02:50]

I think this isn't needed. As I remember it was a speculative attempt to fix
something but nobody remembers what. LGTM.

[cpu_(ooo_6.6-7.5), 2013-07-16 22:42:44]

+Nat for the telemetry fix.

[nduca, 2013-07-16 23:00:14]

lgtm thanks

[commit-bot: I haz the power, 2013-07-16 23:41:09]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/cpu@chromium.org/19114006/7001

[commit-bot: I haz the power, 2013-07-17 03:01:53]

Retried try job too often on chromium_presubmit for step(s) presubmit
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=chromium_p...

[cpu_(ooo_6.6-7.5), 2013-07-17 20:07:10]

john can I get owner's rs ?

[commit-bot: I haz the power, 2013-07-17 23:25:14]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/cpu@chromium.org/19114006/7001

[jam, 2013-07-17 23:30:50]

lgtm

[commit-bot: I haz the power, 2013-07-18 09:41:17]

Change committed as 212308