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

src/gpu/SkGpuDevice.cpp

Index: src/gpu/SkGpuDevice.cpp
diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 158fa912dcbb065e93874d600e9c4bf7699ae228..9a78048aa7f139195a01c0bc0d97756319353da4 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -1832,8 +1832,8 @@ bool SkGpuDevice::EXPERIMENTAL_drawPicture(SkCanvas* mainCanvas, const SkPicture
 
     GrReplacements replacements;
 
-    GrLayerHoister::ConvertLayersToReplacements(needRendering, &replacements);
-    GrLayerHoister::ConvertLayersToReplacements(recycled, &replacements);
+    GrLayerHoister::ConvertLayersToReplacements(mainPicture, needRendering, &replacements);
+    GrLayerHoister::ConvertLayersToReplacements(mainPicture, recycled, &replacements);
 
     // Render the entire picture using new layers
     GrRecordReplaceDraw(mainPicture, mainCanvas, &replacements, initialMatrix, NULL);