Revert of Fix for Incomplete context menu is shown on pdf files and reload,back,forward options are missing

Revert of Fix for Incomplete context menu is shown on pdf files and reload,back,forward options are missing (patchset #4 id:60001 of https://codereview.chromium.org/913663002/)

Reason for revert:
This caused http://code.google.com/p/chromium/issues/detail?id=458927 . There is a followup CL: https://codereview.chromium.org/931073002/ which almost does a revert of this anyway. So I'm reverting here just to be safe and make sure this doesn't make its way to a branch.

Original issue's description:
> Fix for incomplete context menu in pdf page.
>
> when we are viewing the PDF in a MimeHandlerViewGuest then we should
> use its embedder WebContents.
> Changes done to use the embedder WebContents if we have guest view.
>
> BUG=449919
>
> Committed: https://crrev.com/0c6616522ca22a77e444c4b4f57b3b71baf30cdb
> Cr-Commit-Position: refs/heads/master@{#316187}

TBR=lazyboy@chromium.org,avi@chromium.org,deepak.m1@samsung.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=449919
Committed: https://crrev.com/f3d747c00cd36682882b957fb4b4e887a01c8a31
Cr-Commit-Position: refs/heads/master@{#316714}

[raymes, 2015-02-18 00:43:02]

Created Revert of Fix for Incomplete context menu is shown on pdf files and
reload,back,forward options are missing