Add testing for Rectanizer-derived classes

src/gpu/GrRectanizer_pow2.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 GrRectanizer_pow2_DEFINED
+#define GrRectanizer_pow2_DEFINED
+
+#include "GrRectanizer.h"
+
+class GrRectanizerPow2 : public GrRectanizer {
+public:
+    GrRectanizerPow2(int w, int h) : INHERITED(w, h) {
+        this->reset();
+    }
+
+    virtual ~GrRectanizerPow2() { }
+
+    virtual void reset() SK_OVERRIDE {
+        fNextStripY = 0;
+        fAreaSoFar = 0;
+        sk_bzero(fRows, sizeof(fRows));
+    }
+
+    virtual bool addRect(int w, int h, GrIPoint16* loc) SK_OVERRIDE;
+
+    virtual float percentFull() const SK_OVERRIDE {
+        return fAreaSoFar / ((float)this->width() * this->height());
+    }
+
+private:
+    static const int kMIN_HEIGHT_POW2 = 2;
+
+    struct Row {
+        GrIPoint16  fLoc;
+        int         fRowHeight;
+
+        bool canAddWidth(int width, int containerWidth) const {
+            return fLoc.fX + width <= containerWidth;
+        }
+    };
+
+    Row fRows[16];
+
+    int fNextStripY;
+    int32_t fAreaSoFar;
+
+    static int HeightToRowIndex(int height) {
+        SkASSERT(height >= kMIN_HEIGHT_POW2);
+        return 32 - SkCLZ(height - 1);
+    }
+
+    bool canAddStrip(int height) const {
+        return fNextStripY + height <= this->height();
+    }
+
+    void initRow(Row* row, int rowHeight) {
+        row->fLoc.set(0, fNextStripY);
+        row->fRowHeight = rowHeight;
+        fNextStripY += rowHeight;
+    }
+
+    typedef GrRectanizer INHERITED;
+};
+
+#endif