Move the GL shader compilation step into GrGLShaderBuilder

Moves the compilation step and a few other blocks of code from
GrGLProgram to GrGLShaderBuilder. This way GrGLProgram doesn't have to
know whether or not there is a vertex shader.

R=bsalomon@google.com

Author: cdalton@nvidia.com

Review URL: https://codereview.chromium.org/23533066

git-svn-id: http://skia.googlecode.com/svn/trunk@11523 2bbb7eff-a529-9590-31e7-b0007b416f81
6 files changed