Add link to how to generate new SKPs when increasing the picture version

include/core/SkPicture.h

 
 /*
  * Copyright 2007 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkPicture_DEFINED
@@ skipping 221 matching lines @@
     // V12: add conics to SkPath, use new SkPathRef flattening
     // V13: add flag to drawBitmapRectToRect
     //      parameterize blurs by sigma rather than radius
     // V14: Add flags word to PathRef serialization
     // V15: Remove A1 bitmpa config (and renumber remaining configs)
     // V16: Move SkPath's isOval flag to SkPathRef
     // V17: SkPixelRef now writes SkImageInfo
     // V18: SkBitmap now records x,y for its pixelref origin, instead of offset.
     // V19: encode matrices and regions into the ops stream
     // V20: added bool to SkPictureImageFilter's serialization (to allow SkPicture serialization)
+
+    // Note: If the picture version needs to be increased then please follow the
+    // steps to generate new SKPs in (only accessible to Googlers): http://goo.gl/qATVcw
     static const uint32_t PICTURE_VERSION = 20;
 
     // fPlayback, fRecord, fWidth & fHeight are protected to allow derived classes to
     // install their own SkPicturePlayback-derived players,SkPictureRecord-derived
     // recorders and set the picture size
     SkPicturePlayback* fPlayback;
     SkPictureRecord* fRecord;
     int fWidth, fHeight;
 
     // Create a new SkPicture from an existing SkPicturePlayback. Ref count of
@@ skipping 31 matching lines @@
  */
 class SK_API SkDrawPictureCallback {
 public:
     SkDrawPictureCallback() {}
     virtual ~SkDrawPictureCallback() {}
 
     virtual bool abortDrawing() = 0;
 };
 
 #endif