Use variable length key (rather than accumulated matrix) as save layer hoisting key

src/gpu/GrLayerHoister.cpp

Index: src/gpu/GrLayerHoister.cpp
diff --git a/src/gpu/GrLayerHoister.cpp b/src/gpu/GrLayerHoister.cpp
index b53c1b80cdda6be05f85d3e544abeb6572cd51e0..e9680dcee88a6527e598b25432cb24644fb6af57 100644
--- a/src/gpu/GrLayerHoister.cpp
+++ b/src/gpu/GrLayerHoister.cpp
@@ -34,6 +34,8 @@ static void prepare_for_hoisting(GrLayerCache* layerCache,
                                                          info.fRestoreOpID,
                                                          layerRect,
                                                          combined,
+                                                         info.fKey,
+                                                         info.fKeySize,
                                                          info.fPaint);
     GrSurfaceDesc desc;
     desc.fFlags = kRenderTarget_GrSurfaceFlag;
@@ -197,7 +199,7 @@ void GrLayerHoister::ConvertLayersToReplacements(const SkTDArray<GrHoistedLayer>
         GrReplacements::ReplacementInfo* layerInfo =
                     replacements->newReplacement(picture->uniqueID(),
                                                  layer->start(),
-                                                 combined);
+                                                 layer->key(), layer->keySize());
         layerInfo->fStop = layer->stop();
         layerInfo->fPos = layers[i].fOffset;