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

src/gpu/GrProcOptInfo.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrProcOptInfo_DEFINED
+#define GrProcOptInfo_DEFINED
+
+#include "GrColor.h"
+#include "GrInvariantOutput.h"
+
+class GrFragmentStage;
+class GrGeometryProcessor;
+
+class GrProcOptInfo {
+public:
+    GrProcOptInfo()
+        : fInout(0, static_cast<GrColorComponentFlags>(0), false), fFirstEffectStageIndex(0),
+          fInputColorIsUsed(true), fInputColor(0), fRemoveVertexAttrib(false), fReadsDst(false) {}
+
+    void calcWithInitialValues(const GrFragmentStage*, int stageCount, GrColor startColor,
+                               GrColorComponentFlags flags, bool areCoverageStages,
+                               const GrGeometryProcessor* gp = NULL);
+
+    bool isSolidWhite() const { return fInout.isSolidWhite(); }
+    bool isOpaque() const { return fInout.isOpaque(); }
+
+    GrColor color() const { return fInout.color(); }
+    uint8_t validFlags() const { return fInout.validFlags(); }
+
+    int firstEffectiveStageIndex() const { return fFirstEffectStageIndex; }
+    bool inputColorIsUsed() const { return fInputColorIsUsed; }
+    GrColor inputColorToEffectiveStage() const { return fInputColor; }
+    bool removeVertexAttrib() const { return fRemoveVertexAttrib; }
+    bool readsDst() const { return fReadsDst; }
+
+private:
+    GrInvariantOutput fInout;
+    int fFirstEffectStageIndex;
+    bool fInputColorIsUsed;
+    GrColor fInputColor;
+    bool fRemoveVertexAttrib;
+    bool fReadsDst;
+};
+
+#endif