add replay entry point to SkPictureRecorder for Android

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 81 matching lines @@
         if (NULL != fPicture.get()) {
             fPicture->internalOnly_EnableOpts(enableOpts);
         }
     }
 
 private:
 #ifdef SK_SUPPORT_LEGACY_DERIVED_PICTURE_CLASSES
     SkAutoTUnref<SkPictureFactory>  fFactory;
 #endif
 
+#ifdef SK_BUILD_FOR_ANDROID

[mtklein, 2014/04/30 20:20:11]

Is this necessary to build, or just a guard to prevent future use?  Privatizing
and friending in AndroidPicture seems pretty good enough to me, but will get us
better coverage in tests, builds, etc.

[robertphillips, 2014/05/27 14:10:08]

This will build without the Android guard but having it here makes it explicit
that it is Android only.

+    /** Replay the current (partially recorded) operation stream into
+        canvas. This call doesn't close the current recording.
+    */
+    friend class AndroidPicture;
+    friend class SkPictureRecorderReplayTester; // for unit testing
+    void replay(SkCanvas* canvas);

[mtklein, 2014/04/30 20:20:11]

Maybe work "partial" into the name?  replay() sounds like the normal thing you
might do on a picture (like draw), but we want this one to seem niche right?

void drawPartialRecording()?

+#endif
+
     SkAutoTUnref<SkPicture>         fPicture;
 
     typedef SkNoncopyable INHERITED;
 };
 
 #endif