Force shader recompilation when #define variables are passed in.
Force shader recompilation when #define variables are passed in.

Previously, if LoadShader() was called, even if a list of #defines
was passed in, it would return the shader if it had been previously
loaded. It should recompile if such a list is provided.

Bug: Issue 27612150

Tested:
Works on Mac.

Change-Id: I7fa664f93e80c93dcde81f7b9099fba592b7e8f7

google/fplbase,google/fplbase,google/fplbase,google/fplbase