DM::SKPSrc::size() reports correct size.

DM::SKPSrc::size() reports correct size.

Also, DM::GPUSink and DM::RasterSink crop DM::Src::size() to 2048x2048.

Motivation:
  Improve PDF testing by printing the entire SKP.

Source: http://crrev.com/863243004

BUG=skia:3365
Committed: https://skia.googlesource.com/skia/+/441b10eac09a1f44983e35da827a6b438a409e63

CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu12-ShuttleA-GTX660-x86-Release-Trybot,Test-ChromeOS-Alex-GMA3150-x86-Release-Trybot

Committed: https://skia.googlesource.com/skia/+/d4dd58e43ca4551531ad6a9f54bfc5632ea45a80

[hal.canary, 2015-01-28 19:04:32]

halcanary@google.com changed reviewers:
+ halcanary@google.com

[hal.canary, 2015-01-28 19:04:33]

lgtm

[hal.canary, 2015-01-28 19:04:39]

The CQ bit was checked by halcanary@google.com

[commit-bot: I haz the power, 2015-01-28 19:04:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/863243005/1

[commit-bot: I haz the power, 2015-01-28 19:12:29]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/441b10eac09a1f44983e35da827a6b438a409e63

[mtklein, 2015-01-28 20:03:15]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/884743003/ by mtklein@google.com.

The reason for reverting is: OOM on 32-bit machines..

[mtklein, 2015-01-28 21:48:43]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-01-28 21:49:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/863243005/40001

[commit-bot: I haz the power, 2015-01-28 21:59:45]

Committed patchset #3 (id:40001) as
https://skia.googlesource.com/skia/+/d4dd58e43ca4551531ad6a9f54bfc5632ea45a80

[mtklein, 2015-01-28 23:31:31]

A revert of this CL (patchset #3 id:40001) has been created in
https://codereview.chromium.org/886543005/ by mtklein@google.com.

The reason for reverting is: Still no good on Chrome OS bot:

http://build.chromium.org/p/client.skia/builders/Test-ChromeOS-Alex-GMA3150-x....