Allow previously-hoisted layers to be reused in the same draw

src/gpu/GrLayerHoister.h

Index: src/gpu/GrLayerHoister.h
diff --git a/src/gpu/GrLayerHoister.h b/src/gpu/GrLayerHoister.h
index 6aff2ea32abe45965a49e298b12165e84edf75fa..58b3f4870ba2f809a1a3554a1b50216eebd22b5f 100644
--- a/src/gpu/GrLayerHoister.h
+++ b/src/gpu/GrLayerHoister.h
@@ -36,6 +36,7 @@ public:
         @param query       The rectangle that is about to be drawn.
         @param atlased     Out parameter storing the layers that should be hoisted to the atlas
         @param nonAtlased  Out parameter storing the layers that should be hoisted stand alone
+        @param recycled    Out parameter storing layers that need hoisting but not rendering
         @param layerCache The source of new layers
         Return true if any layers are suitable for hoisting; false otherwise
     */
@@ -43,25 +44,31 @@ public:
                                   const SkRect& query,
                                   SkTDArray<HoistedLayer>* altased,
                                   SkTDArray<HoistedLayer>* nonAtlased,
+                                  SkTDArray<HoistedLayer>* recycled,
                                   GrLayerCache* layerCache);
 
     /** Draw the specified layers into either the atlas or free floating textures.
         @param atlased      The layers to be drawn into the atlas
         @param nonAtlased   The layers to be drawn into their own textures
-        @oaram replacements The replacement structure to fill in with the rendered layer info
+        @param recycled     Layers that don't need rendering but do need to go into the 
+                            replacements object
+        @param replacements The replacement structure to fill in with the rendered layer info
     */
     static void DrawLayers(const SkTDArray<HoistedLayer>& atlased,
                            const SkTDArray<HoistedLayer>& nonAtlased,
+                           const SkTDArray<HoistedLayer>& recycled,
                            GrReplacements* replacements);
 
     /** Unlock unneeded layers in the layer cache.
         @param layerCache holder of the locked layers
         @param atlased    Unneeded layers in the atlas
         @param nonAtlased Unneeded layers in their own textures
+        @param recycled   Unneeded layers that did not require rendering
     */
     static void UnlockLayers(GrLayerCache* layerCache,
                              const SkTDArray<HoistedLayer>& atlased,
-                             const SkTDArray<HoistedLayer>& nonAtlased);
+                             const SkTDArray<HoistedLayer>& nonAtlased,
+                             const SkTDArray<HoistedLayer>& recycled);
 };
 
 #endif