Merge pull request #20041 from davidflanagan/bug1020273

Bug 1020273: make the Gallery crop handles more sensitive r=pdahiya(cherry picked from commit a44346be68f23782d6b24426ed085d62856f9273)
Merge pull request #20172 from davidflanagan/bug1020273-v1.3t

Bug1020273 v1.3t