pdfviewer: when q start, and an operator is called, it should not be able to see operands before q. nest/unnest are similar with pop/push - simulates a stack of stacks, in a single stack

Review URL: https://codereview.chromium.org/23033022

git-svn-id: http://skia.googlecode.com/svn/trunk@10873 2bbb7eff-a529-9590-31e7-b0007b416f81
5 files changed