Split SkPictureRangePlayback out of SkPicturePlayback

src/core/SkPictureRangePlayback.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 "SkCanvas.h"
+#include "SkPictureData.h"
+#include "SkPictureRangePlayback.h"
+
+void SkPictureRangePlayback::draw(SkCanvas* canvas, SkDrawPictureCallback* callback) {
+    AutoResetOpID aroi(this);
+    SkASSERT(0 == fCurOffset);
+
+    SkReader32 reader(fPictureData->opData()->bytes(), fPictureData->opData()->size());
+
+    if (0 != fStart || 0 != fStop) {
+        reader.setOffset(fStart);
+        uint32_t size;
+        SkDEBUGCODE(DrawType op = ) ReadOpAndSize(&reader, &size);
+        SkASSERT(SAVE_LAYER == op);
+        reader.setOffset(fStart + size);
+    }
+
+    // Record this, so we can concat w/ it if we encounter a setMatrix()
+    SkMatrix initialMatrix = canvas->getTotalMatrix();
+
+    SkAutoCanvasRestore acr(canvas, false);
+
+    while (!reader.eof()) {
+        if (callback && callback->abortDrawing()) {
+            return;
+        }
+
+        if (0 != fStart || 0 != fStop) {
+            size_t offset = reader.offset();
+            if (offset >= fStop) {
+                SkDEBUGCODE(uint32_t size;)
+                SkDEBUGCODE(DrawType op = ReadOpAndSize(&reader, &size);)
+                SkASSERT(RESTORE == op);
+                return;
+            }
+        }
+
+        fCurOffset = reader.offset();
+        uint32_t size;
+        DrawType op = ReadOpAndSize(&reader, &size);
+        if (NOOP == op) {
+            // NOOPs are to be ignored - do not propagate them any further
+            reader.setOffset(fCurOffset + size);
+            continue;
+        }
+
+        this->handleOp(&reader, op, size, canvas, initialMatrix);
+    }
+}