SkPDF: clean up uses of deprecated calls in SkPDFDevice

SkPDF: clean up uses of deprecated calls in SkPDFDevice.

Clean up reference count handling to avoid churn and follow pattern used elsewhere in SkPDF.

BUG=skia:3585
Committed: https://skia.googlesource.com/skia/+/438de49857cab98981b35d04dc49c2135124d18b

[hal.canary, 2015-04-27 12:26:22]

The CQ bit was checked by halcanary@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-04-27 12:26:24]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1103163002/1

[hal.canary, 2015-04-27 12:26:55]

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

[hal.canary, 2015-04-27 12:26:55]

PTAL

[commit-bot: I haz the power, 2015-04-27 12:32:51]

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

[commit-bot: I haz the power, 2015-04-27 12:32:51]

Dry run: This issue passed the CQ dry run.

[tomhudson, 2015-04-27 15:49:41]

I'd like to understand *why* this is a good change to make.

Modulo that, tentative LGTM.

[hal.canary, 2015-04-28 13:15:48]

https://codereview.chromium.org/1103163002/diff/1/src/pdf/SkPDFDevice.h
File src/pdf/SkPDFDevice.h (right):

https://codereview.chromium.org/1103163002/diff/1/src/pdf/SkPDFDevice.h#newco...
src/pdf/SkPDFDevice.h:300: void addAnnotation(SkPDFDict*);
To reduce reference-churn and increase pointer safety, I am reorganizing this
function to first, create an annotation object, then finish adding information
to the object, and then finally detach() it and add it to the list of
annotations.

[hal.canary, 2015-04-28 13:15:55]

The CQ bit was checked by halcanary@google.com

[commit-bot: I haz the power, 2015-04-28 13:16:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1103163002/1

[commit-bot: I haz the power, 2015-04-28 13:21:07]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/438de49857cab98981b35d04dc49c2135124d18b