Make conversion between CPDF_Action and its dictionary explicit

Make conversion between CPDF_Action and its dictionary explicit.

Precursor to taking a second shot at cleaning up the FPDF_*
APIs.  A FPDF_Action is a CPDF_Dictionary, and a CPDF_Action
is a structure holding a FPDF_Action.  This goes against the
convention that FPDF_ types get cast to CPDF_* types, so we
want to make it clear where objects are getting constructed,
etc.

Also tidy fpdf_actionhandler.cpp because it bugs me.

R=thestig@chromium.org

Committed: https://pdfium.googlesource.com/pdfium/+/624b6c1e0fc6a5b0467061ef37b6db6856681afb

[Tom Sepez, 2015-03-06 00:00:38]

tsepez@chromium.org changed reviewers:
+ thestig@chromium.org

[Tom Sepez, 2015-03-06 00:00:38]

Lei, please review.

[Lei Zhang, 2015-03-06 00:17:05]

lgtm

https://codereview.chromium.org/984773002/diff/1/fpdfsdk/src/fsdk_baseform.cpp
File fpdfsdk/src/fsdk_baseform.cpp (right):

https://codereview.chromium.org/984773002/diff/1/fpdfsdk/src/fsdk_baseform.cp...
fpdfsdk/src/fsdk_baseform.cpp:1636: return CPDFSDK_Annot::GetAAction(eAAT);
weird indentation, ditto below

https://codereview.chromium.org/984773002/diff/1/fpdfsdk/src/fsdk_mgr.cpp
File fpdfsdk/src/fsdk_mgr.cpp (right):

https://codereview.chromium.org/984773002/diff/1/fpdfsdk/src/fsdk_mgr.cpp#new...
fpdfsdk/src/fsdk_mgr.cpp:428: return FALSE;
Once again, 4-space tabs + 8 spaces do not match up correctly. Just kill the
tabs?

[Tom Sepez, 2015-03-06 00:26:00]

>
https://codereview.chromium.org/984773002/diff/1/fpdfsdk/src/fsdk_mgr.cpp#new...
> fpdfsdk/src/fsdk_mgr.cpp:428: return FALSE;
> Once again, 4-space tabs + 8 spaces do not match up correctly. Just kill the
> tabs?
Darn, I thought I'd configured my editor to avoid this.  Sorry.

[Tom Sepez, 2015-03-06 00:30:16]

Committed patchset #2 (id:20001) manually as
624b6c1e0fc6a5b0467061ef37b6db6856681afb (presubmit successful).