Move GrInvariantOutput out of GrProcessor and into its own class.

This will help with the ability to subclass, add to, etc. GrInvariantOutput. Also it was simply
getting a little too big to be a "supporting" subclass
BUG=skia:

Review URL: https://codereview.chromium.org/699943003
diff --git a/src/gpu/effects/GrSimpleTextureEffect.cpp b/src/gpu/effects/GrSimpleTextureEffect.cpp
index 4da9e8e..9c0ff35 100644
--- a/src/gpu/effects/GrSimpleTextureEffect.cpp
+++ b/src/gpu/effects/GrSimpleTextureEffect.cpp
@@ -5,13 +5,14 @@
  * found in the LICENSE file.
  */
 
-#include "gl/builders/GrGLProgramBuilder.h"
 #include "GrSimpleTextureEffect.h"
+#include "GrInvariantOutput.h"
+#include "GrTBackendProcessorFactory.h"
+#include "GrTexture.h"
 #include "gl/GrGLProcessor.h"
 #include "gl/GrGLSL.h"
 #include "gl/GrGLTexture.h"
-#include "GrTBackendProcessorFactory.h"
-#include "GrTexture.h"
+#include "gl/builders/GrGLProgramBuilder.h"
 
 class GrGLSimpleTextureEffect : public GrGLFragmentProcessor {
 public:
@@ -41,7 +42,7 @@
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void GrSimpleTextureEffect::onComputeInvariantOutput(InvariantOutput* inout) const {
+void GrSimpleTextureEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
     this->updateInvariantOutputForModulation(inout);
 }