Remove GrGLSLSampler type and subclasses

GrGLSLUniformManager and GrGLSLProgramDataManager subclasses handle sampler variation across GPU backends.

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=5002

Change-Id: I968b006bab978c2fa209d1f7eda710c298d1212f
Reviewed-on: https://skia-review.googlesource.com/5002
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/gl/GrGLProgram.cpp b/src/gpu/gl/GrGLProgram.cpp
index 27361e7..1f2e1c8 100644
--- a/src/gpu/gl/GrGLProgram.cpp
+++ b/src/gpu/gl/GrGLProgram.cpp
@@ -31,7 +31,7 @@
                          const BuiltinUniformHandles& builtinUniforms,
                          GrGLuint programID,
                          const UniformInfoArray& uniforms,
-                         const SkTArray<GrGLSampler>& samplers,
+                         const UniformInfoArray& samplers,
                          const VaryingInfoArray& pathProcVaryings,
                          GrGLSLPrimitiveProcessor* geometryProcessor,
                          GrGLSLXferProcessor* xferProcessor,