Add a requiresVertexShader method to GrGLEffect

Add a requiresVertexShader method to GrGLEffect

Adds requiresVertexShader to GrGLEffect and updates the necessary
effects to override it and return true. Also reworks GrGLProgram
and GrGLShaderBuilder so the program creates all the GL effects
at the beginning, and determines if it needs a vertex shader before
creating the shader builder.

R=bsalomon@google.com

Author: cdalton@nvidia.com

Review URL: https://chromiumcodereview.appspot.com/23471008

git-svn-id: http://skia.googlecode.com/svn/trunk@11140 2bbb7eff-a529-9590-31e7-b0007b416f81