Add EXPERIMENTAL_beginRecording() for SkRecord-based recording.

src/record/SkRecordDraw.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 SkRecordDraw_DEFINED
-#define SkRecordDraw_DEFINED
-
-#include "SkRecord.h"
-#include "SkCanvas.h"
-
-// Draw an SkRecord into an SkCanvas.  A convenience wrapper around SkRecords::Draw.
-void SkRecordDraw(const SkRecord&, SkCanvas*);
-
-namespace SkRecords {
-
-// This is an SkRecord visitor that will draw that SkRecord to an SkCanvas.
-class Draw : SkNoncopyable {
-public:
-    explicit Draw(SkCanvas* canvas)
-        : fInitialCTM(canvas->getTotalMatrix()), fCanvas(canvas), fIndex(0) {}
-
-    unsigned index() const { return fIndex; }
-    void next() { ++fIndex; }
-
-    template <typename T> void operator()(const T& r) {
-        if (!this->skip(r)) {
-            this->draw(r);
-        }
-    }
-
-private:
-    // No base case, so we'll be compile-time checked that we implement all possibilities.
-    template <typename T> void draw(const T&);
-
-    // skip() should return true if we can skip this command, false if not.
-    // It may update fIndex directly to skip more than just this one command.
-
-    // Mostly we just blindly call fCanvas and let it handle quick rejects itself.
-    template <typename T> bool skip(const T&) { return false; }
-
-    // We add our own quick rejects for commands added by optimizations.
-    bool skip(const PairedPushCull&);
-    bool skip(const BoundedDrawPosTextH&);
-
-    const SkMatrix fInitialCTM;
-    SkCanvas* fCanvas;
-    unsigned fIndex;
-};
-
-}  // namespace SkRecords
-
-#endif//SkRecordDraw_DEFINED