Remove calls to new when modifying shader constants. There were some unnecessary temporary copies we can remove, and the rest have a maximum size so we can allocate them on the stack. BUG=276 TEST= Review URL: https://codereview.appspot.com/5540071 git-svn-id: https://angleproject.googlecode.com/svn/trunk@961 736b8ea6-26fd-11df-bfd4-992fa37f6226