DM: allow SKPs to be smaller than 1000x1000

DM: allow SKPs to be smaller than 1000x1000

This sniffs the .skp dimensions and intersects them with our 1000x1000 viewport.

This fixes things like desk_carsvg.skp, which is only 902 pixels tall.  In 565 now,
the remaining 98 pixels draw as black, which looks funny and is confusing to triage.

No apparent affect on DM memory usage.  (We're about to map the file anyway.)

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/ffa901aa7e360ed5115a0955221f4c2d2632d418

[mtklein_C, 2015-03-08 17:24:34]

mtklein@chromium.org changed reviewers:
+ halcanary@google.com

[mtklein_C, 2015-03-08 17:24:38]

The CQ bit was checked by mtklein@chromium.org

[commit-bot: I haz the power, 2015-03-08 17:24:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/986103002/1

[commit-bot: I haz the power, 2015-03-08 17:24:58]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2015-03-08 23:24 UTC

[commit-bot: I haz the power, 2015-03-08 23:24:57]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-03-08 23:24:58]

No LGTM from a valid reviewer yet. Please ask for an LGTM from a
full Skia committer from
https://skia.googlesource.com/skia/+/master/CQ_COMMITTERS

[hal.canary, 2015-03-16 16:32:17]

lgtm

[mtklein, 2015-03-16 17:18:05]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-03-16 17:18:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/986103002/1

[commit-bot: I haz the power, 2015-03-16 17:38:10]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/ffa901aa7e360ed5115a0955221f4c2d2632d418