added support for PLS path rendering

src/gpu/GrPLSGeometryProcessor.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrPLSGeometryProcessor_DEFINED
+#define GrPLSGeometryProcessor_DEFINED
+
+#include "GrGeometryProcessor.h"
+
+/**
+ * A minor extension to GrGeometryProcessor that adds bounds tracking for pixel local storage
+ * purposes.
+ */
+class GrPLSGeometryProcessor : public GrGeometryProcessor {
+public:
+    GrPixelLocalStorageState getPixelLocalStorageState() const override { 
+        return GrPixelLocalStorageState::kDraw_GrPixelLocalStorageState;
+    }
+
+    const SkRect& getBounds() const {
+       return fBounds;
+    }
+
+    void setBounds(SkRect& bounds) {
+       fBounds = bounds;
+    }
+
+private:
+    SkRect fBounds;
+};
+
+#endif