Move GrInvariantOutput out of GrProcessor and into its own class.

src/gpu/GrInvariantOutput.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrInvariantOutput.h"
+
+#ifdef SK_DEBUG
+
+void GrInvariantOutput::validate() const {
+    if (fIsSingleComponent) {
+        SkASSERT(0 == fValidFlags || kRGBA_GrColorComponentFlags == fValidFlags);
+        if (kRGBA_GrColorComponentFlags == fValidFlags) {
+            SkASSERT(this->colorComponentsAllEqual());
+        }
+    }
+
+    SkASSERT(this->validPreMulColor());
+
+    // If we claim that we are not using the input color we must not be modulating the input.
+    SkASSERT(fNonMulStageFound || fWillUseInputColor);
+}
+
+bool GrInvariantOutput::colorComponentsAllEqual() const {
+    unsigned colorA = GrColorUnpackA(fColor);
+    return(GrColorUnpackR(fColor) == colorA &&
+           GrColorUnpackG(fColor) == colorA &&
+           GrColorUnpackB(fColor) == colorA);
+}
+
+bool GrInvariantOutput::validPreMulColor() const {
+    if (kA_GrColorComponentFlag & fValidFlags) {
+        float c[4];
+        GrColorToRGBAFloat(fColor, c);
+        if (kR_GrColorComponentFlag & fValidFlags) {
+            if (c[0] > c[3]) {
+                return false;
+            }
+        }
+        if (kG_GrColorComponentFlag & fValidFlags) {
+            if (c[1] > c[3]) {
+                return false;
+            }
+        }
+        if (kB_GrColorComponentFlag & fValidFlags) {
+            if (c[2] > c[3]) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+#endif // end DEBUG
+