Android infobar cleanup:

Android infobar cleanup:

* Don't return values callers don't use
* Rename a temp in anticipation of refactor patch
* Use Pass() where PassAs<>() is not necessary
* Minor comment/whitespace changes
* Don't NULL-check web_contents() when we're owned (should never be NULL)
* Don't bother storing delegate pointers on infobar subclasses, just downcast
  the base class' pointer (matches other platforms)
* Remove unnecessary DCHECKs (either other code performs them or they will no
  longer be necesssary in the refactored world)
* Remove unnecessary temps
* Speed up vector manipulation by not creating a bunch of objects we then
  overwrite
* DCHECK(expected, actual)

BUG=none
TEST=none
R=miguelg@chromium.org

Review URL: https://codereview.chromium.org/77773005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236640 0039d316-1c4b-4281-b951-d872f2087c98