[Android] Provide fallback scaling constants in ViewConfiguration

Certain devices may lack the internal Android dimension lookups for
MinScalingSpan and MinScalingTouchMajor.  Provide sensible default backups
for this case.

BUG=345602
NOTRY=true

Review URL: https://codereview.chromium.org/175493002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252641 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252641