athena: Add support for PDF

athena: Add support for PDF.

Advertise support for PDF plugins, and use the implementations from the
pdf component (in //components/pdf) for adding the necessary support for
showing PDF files in athena.

BUG=401242
R=jamescook@chromium.org, oshima@chromium.org, raymes@chromium.org

Committed: https://crrev.com/8d7df02b9f6ac93a1f0383ff06af82de5c6813ee
Cr-Commit-Position: refs/heads/master@{#292684}

[sadrul, 2014-08-28 23:07:45]

sadrul@chromium.org changed reviewers:
+ jamescook@chormium.org, oshima@chromium.org, raymes@chromium.org

[sadrul, 2014-08-28 23:07:45]

oshima@ all changes

jamescook@ all changes + owner for DEPS addition to extensions/shell/common

raymes@ owner for DEPS additions to ppapi and components/pdf

[raymes, 2014-08-29 01:16:54]

On 2014/08/28 23:07:45, sadrul wrote:
> oshima@ all changes
> 
> jamescook@ all changes + owner for DEPS addition to extensions/shell/common
> 
> raymes@ owner for DEPS additions to ppapi and components/pdf

lgtm

[oshima, 2014-08-29 18:00:07]

we may want to restructure the dir/code for main/app_shell, but lgtm for now.

[James Cook, 2014-08-29 21:21:37]

jamescook@chromium.org changed reviewers:
+ jamescook@chromium.org

[James Cook, 2014-08-29 21:21:38]

lgtm

[sadrul, 2014-08-29 21:33:36]

Committed patchset #17 (id:320001) manually as 8d7df02 (presubmit successful).

[commit-bot: I haz the power, 2014-09-10 03:10:36]

Patchset 17 (id:??) landed as
https://crrev.com/8d7df02b9f6ac93a1f0383ff06af82de5c6813ee
Cr-Commit-Position: refs/heads/master@{#292684}