Make pinch-zoom work for OOP PDF

Make pinch-zoom work for OOP PDF

There are two changes to make this work:
-Set the plugins width/height to 100%. We will soon be using this for the material layout as well.
-Allow MimeHandlerViewGuests to handle pinch gestures when they are full-page plugins.

BUG=453729
Committed: https://crrev.com/f0db15c17e5abb7c6dccdc11bcfffcb2d8ce835c
Cr-Commit-Position: refs/heads/master@{#314742}

[raymes, 2015-02-05 02:11:33]

raymes@chromium.org changed reviewers:
+ fsamuel@chromium.org, sammc@chromium.org

[Fady Samuel, 2015-02-05 02:24:59]

guest_view lgtm

[Sam McNally, 2015-02-05 02:43:17]

lgtm

[raymes, 2015-02-05 02:57:19]

The CQ bit was checked by raymes@chromium.org

[commit-bot: I haz the power, 2015-02-05 02:58:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/904553002/1

[commit-bot: I haz the power, 2015-02-05 03:55:25]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-05 03:56:44]

Patchset 1 (id:??) landed as
https://crrev.com/f0db15c17e5abb7c6dccdc11bcfffcb2d8ce835c
Cr-Commit-Position: refs/heads/master@{#314742}