Revert of rename SkCanvasDrawable to SkDrawable, and make public

include/core/SkPictureRecorder.h

Index: include/core/SkPictureRecorder.h
diff --git a/include/core/SkPictureRecorder.h b/include/core/SkPictureRecorder.h
index b25e26b26a824e7e72ea10268f90ea70dcbbcd79..14443b23d8fcc3bdbc5d20a4119455cffc3993b0 100644
--- a/include/core/SkPictureRecorder.h
+++ b/include/core/SkPictureRecorder.h
@@ -19,7 +19,7 @@
 #endif
 
 class SkCanvas;
-class SkDrawable;
+class SkCanvasDrawable;
 class SkPictureRecord;
 class SkRecord;
 class SkRecorder;
@@ -79,7 +79,7 @@
      *  and therefore this drawable will reflect the current state of those nested drawables anytime
      *  it is drawn or a new picture is snapped from it (by calling drawable->newPictureSnapshot()).
      */
-    SkDrawable* endRecordingAsDrawable();
+    SkCanvasDrawable* EXPERIMENTAL_endRecordingAsDrawable();
 
     // Legacy API -- use endRecordingAsPicture instead.
     SkPicture* endRecording() { return this->endRecordingAsPicture(); }