remove subclassing from ImageFilter::Proxy

src/core/SkDeviceImageFilterProxy.h

-/*
- * Copyright 2012 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 SkDeviceImageFilterProxy_DEFINED
-#define SkDeviceImageFilterProxy_DEFINED
-
-#include "SkBitmapDevice.h"
-#include "SkDevice.h"
-#include "SkImageFilter.h"
-#include "SkSurfaceProps.h"
-
-class SkDeviceImageFilterProxy : public SkImageFilter::Proxy {
-public:
-    SkDeviceImageFilterProxy(SkBaseDevice* device, const SkSurfaceProps& props)
-        : fDevice(device)
-        , fProps(props.flags(), kUnknown_SkPixelGeometry)
-    {}
-
-    SkBaseDevice* createDevice(int w, int h) override {
-        SkBaseDevice::CreateInfo cinfo(SkImageInfo::MakeN32Premul(w, h),
-                                       SkBaseDevice::kNever_TileUsage,
-                                       kUnknown_SkPixelGeometry,
-                                       true /*forImageFilter*/);
-        SkBaseDevice* dev = fDevice->onCreateDevice(cinfo, NULL);
-        if (NULL == dev) {
-            dev = SkBitmapDevice::Create(cinfo.fInfo);
-        }
-        return dev;
-    }
-    bool filterImage(const SkImageFilter* filter, const SkBitmap& src,
-                     const SkImageFilter::Context& ctx, SkBitmap* res, SkIPoint* offset) override {
-        return fDevice->filterImage(filter, src, ctx, res, offset);
-    }
-    const SkSurfaceProps* surfaceProps() const override {
-        return &fProps;
-    }
-
-private:
-    SkBaseDevice*  fDevice;
-    const SkSurfaceProps fProps;
-};
-
-#endif