Add GrProcOptInfo class to track various output information for color and coverage stages.

src/gpu/GrProcessor.cpp

Index: src/gpu/GrProcessor.cpp
diff --git a/src/gpu/GrProcessor.cpp b/src/gpu/GrProcessor.cpp
index 31f0004e68f9f238ef8152076850d06fd5d7880c..01071dabfd7a42f9efeb56c1f2b2d55375a4d5ed 100644
--- a/src/gpu/GrProcessor.cpp
+++ b/src/gpu/GrProcessor.cpp
@@ -130,11 +130,7 @@ bool GrProcessor::hasSameTextureAccesses(const GrProcessor& that) const {
 }
 
 void GrProcessor::computeInvariantOutput(GrInvariantOutput* inout) const {
-    inout->resetWillUseInputColor();
     this->onComputeInvariantOutput(inout);

[egdaniel, 2014/11/12 19:27:46]

In a follow up cl I will remove the virtual onComputeIO and simply make
computeIO the virtual call. I didn't want to clog up this cl with logs of simple
replacement changes

-#ifdef SK_DEBUG
-    inout->validate();
-#endif
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////