Revert "Revert "SkImageInfoValidConversion (part 2)""

Revert "Revert "SkImageInfoValidConversion (part 2)""

This reverts commit 8dadd9e8936a1c8f44fccdfde7f883dfe2d89c96.

Reason for revert: Fixed Chrome.  This should roll now.

Original change's description:
> Revert "SkImageInfoValidConversion (part 2)"
>
> This reverts commit 94bd50cc5575b90eb60234399d69905b8651c27e.
>
> Reason for revert: Still breaking roll
>
> Original change's description:
> > SkImageInfoValidConversion (part 2)
> >
> > Disabling non-opaque -> opaque should be fine now that the
> > Chrome unit test has been fixed.
> >
> > BUG=skia:6021
> >
> > Change-Id: I39f087e2695bdefacf793bd137931e3115ec58cb
> > Reviewed-on: https://skia-review.googlesource.com/7121
> > Reviewed-by: Brian Osman <brianosman@google.com>
> > Commit-Queue: Matt Sarett <msarett@google.com>
> >
>
> TBR=msarett@google.com,brianosman@google.com
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=skia:6021
>
> Change-Id: I79843ea6cf60ca94822446c548f3386706924ee6
> Reviewed-on: https://skia-review.googlesource.com/7164
> Commit-Queue: Matt Sarett <msarett@google.com>
> Reviewed-by: Matt Sarett <msarett@google.com>
>

TBR=msarett@google.com,brianosman@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:6021

Change-Id: I40a85ac2e407de15916f0893d55163aea44157cb
Reviewed-on: https://skia-review.googlesource.com/7181
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Matt Sarett <msarett@google.com>