For example: varying variables, uniforms.

This CL makes MapLongVariableNames a ref-counted singleton and therefore, the map is shared by all shaders.

Also, function/variable names changes from Varying to Global because uniforms also need to be consistent, not just varying variables.

ANGLEBUG=279
TEST=webgl conformance tests, especially invalid-passed-params.html and glsl-long-variable-names.html
Review URL: http://codereview.appspot.com/5539046

git-svn-id: https://angleproject.googlecode.com/svn/trunk@942 736b8ea6-26fd-11df-bfd4-992fa37f6226