Revert of removing GrDrawEffect

include/gpu/GrDrawEffect.h

Index: include/gpu/GrDrawEffect.h
diff --git a/include/gpu/GrDrawEffect.h b/include/gpu/GrDrawEffect.h
new file mode 100644
index 0000000000000000000000000000000000000000..710b00035ff8757b5367e78579ff523811d277a5
--- /dev/null
+++ b/include/gpu/GrDrawEffect.h
@@ -0,0 +1,47 @@
+
+#ifndef GrDrawEffect_DEFINED
+#define GrDrawEffect_DEFINED
+
+#include "GrEffectStage.h"
+
+/**
+ * This class is used to communicate the particular GrEffect used in a draw to the backend-specific
+ * effect subclass (e.g. GrGLEffect). It is used to by the backend-specific class to generate a
+ * cache key for the effect, generate code on a program cache miss, and to upload uniform values to
+ * the program.
+ * In addition to the effect, it also communicates any changes between the relationship between
+ * the view matrix and local coordinate system since the effect was installed in its GrDrawState.
+ * The typical use case is that sometime after an effect was installed a decision was made to draw
+ * in device coordinates (i.e. use an identity view-matrix). In such a case the GrDrawEffect's
+ * coord-change-matrix would be the inverse of the view matrix that was set when the effect was
+ * installed.
+ */
+class GrDrawEffect {
+public:
+    GrDrawEffect(const GrEffectStage& stage, bool explicitLocalCoords)
+        : fEffectStage(&stage)
+        , fExplicitLocalCoords(explicitLocalCoords) {
+        SkASSERT(fEffectStage);
+        SkASSERT(fEffectStage->getEffect());
+    }
+    const GrEffect* effect() const { return fEffectStage->getEffect(); }
+
+    template <typename T>
+    const T& castEffect() const { return *static_cast<const T*>(this->effect()); }
+
+    const SkMatrix& getCoordChangeMatrix() const {
+        if (fExplicitLocalCoords) {
+            return SkMatrix::I();
+        } else {
+            return fEffectStage->getCoordChangeMatrix();
+        }
+    }
+
+    bool programHasExplicitLocalCoords() const { return fExplicitLocalCoords; }
+
+private:
+    const GrEffectStage*    fEffectStage;
+    bool                    fExplicitLocalCoords;
+};
+
+#endif