WIP RasterCanvasLayerAllocator experiment 2

src/core/SkBitmapDevice.cpp

Index: src/core/SkBitmapDevice.cpp
diff --git a/src/core/SkBitmapDevice.cpp b/src/core/SkBitmapDevice.cpp
index 4f8074d3a672ea0df255a09cc540b5c726e552fa..35d16b3c0530f29c37a09999aef6ae128df7c33d 100644
--- a/src/core/SkBitmapDevice.cpp
+++ b/src/core/SkBitmapDevice.cpp
@@ -11,11 +11,13 @@
 #include "SkImageFilter.h"
 #include "SkImageFilterCache.h"
 #include "SkMallocPixelRef.h"
+#include "SkManagedBitmapDevice.h"
 #include "SkMatrix.h"
 #include "SkPaint.h"
 #include "SkPath.h"
 #include "SkPixelRef.h"
 #include "SkPixmap.h"
+#include "SkRasterCanvasLayerAllocator.h"
 #include "SkRasterClip.h"
 #include "SkShader.h"
 #include "SkSpecialImage.h"
@@ -134,8 +136,12 @@ void SkBitmapDevice::replaceBitmapBackendForRasterSurface(const SkBitmap& bm) {
     this->privateResize(fBitmap.info().width(), fBitmap.info().height());
 }
 
-SkBaseDevice* SkBitmapDevice::onCreateDevice(const CreateInfo& cinfo, const SkPaint*) {
+SkBaseDevice* SkBitmapDevice::onCreateDevice(const CreateInfo& cinfo, const SkPaint*,
+                                             SkRasterCanvasLayerAllocator* allocator) {
     const SkSurfaceProps surfaceProps(this->surfaceProps().flags(), cinfo.fPixelGeometry);
+    if (allocator) {
+        return allocator->makeDevice(cinfo.fInfo, surfaceProps);
+    }
     return SkBitmapDevice::Create(cinfo.fInfo, surfaceProps);
 }