Install a hook to swap between SkPicture backends with a single define.

include/core/SkPictureRecorder.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 SkPictureRecorder_DEFINED
 #define SkPictureRecorder_DEFINED
 
@@ skipping 23 matching lines @@
         @param height the base width for the picture, as if the recording
                      canvas' bitmap had this height.
         @param bbhFactory factory to create desired acceleration structure
         @param recordFlags optional flags that control recording.
         @return the canvas.
     */
     SkCanvas* beginRecording(int width, int height,
                              SkBBHFactory* bbhFactory = NULL,
                              uint32_t recordFlags = 0);
 
-    /** Same as beginRecording(), using a new faster backend. */
+    // As usual, we have a deprecated old version and a maybe almost working
+    // new version.  We currently point beginRecording() to
+    // DEPRECATED_beginRecording() unless SK_PICTURE_USE_SK_RECORD is defined,
+    // then we use EXPERIMENTAL_beginRecording().
+
+    // Old slower backend.
+    SkCanvas* DEPRECATED_beginRecording(int width, int height,
+                                        SkBBHFactory* bbhFactory = NULL,
+                                        uint32_t recordFlags = 0);
+
+    // New faster backend.
     SkCanvas* EXPERIMENTAL_beginRecording(int width, int height,
                                           SkBBHFactory* bbhFactory = NULL);
 
     /** Returns the recording canvas if one is active, or NULL if recording is
         not active. This does not alter the refcnt on the canvas (if present).
     */
     SkCanvas* getRecordingCanvas();
 
     /** Signal that the caller is done recording. This invalidates the canvas
         returned by beginRecording/getRecordingCanvas, and returns the
@@ skipping 31 matching lines @@
     SkAutoTUnref<SkPictureRecord> fPictureRecord;  // beginRecording()
     SkAutoTUnref<SkRecorder>      fRecorder;       // EXPERIMENTAL_beginRecording()
 
     // Used by EXPERIMENTAL_beginRecording().
     SkAutoTDelete<SkRecord> fRecord;
 
     typedef SkNoncopyable INHERITED;
 };
 
 #endif