impl preroll for all image backends

src/image/SkImage_Raster.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkImage_Base.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
@@ skipping 46 matching lines @@
             *minSize = size;
         }
         return true;
     }
 
     SkImage_Raster(const SkImageInfo&, SkData*, size_t rb, SkColorTable*, const SkSurfaceProps*);
     virtual ~SkImage_Raster();
 
     SkSurface* onNewSurface(const SkImageInfo&, const SkSurfaceProps&) const override;
     bool onReadPixels(const SkImageInfo&, void*, size_t, int srcX, int srcY) const override;
-    void onPreroll(GrContext*) const override;
     const void* onPeekPixels(SkImageInfo*, size_t* /*rowBytes*/) const override;
     SkData* onRefEncoded() const override;
     bool getROPixels(SkBitmap*) const override;
 
     // exposed for SkSurface_Raster via SkNewImageFromPixelRef
     SkImage_Raster(const SkImageInfo&, SkPixelRef*, const SkIPoint& pixelRefOrigin, size_t rowBytes,
                    const SkSurfaceProps*);
 
     SkPixelRef* getPixelRef() const { return fBitmap.pixelRef(); }
 
@@ skipping 79 matching lines @@
 const void* SkImage_Raster::onPeekPixels(SkImageInfo* infoPtr, size_t* rowBytesPtr) const {
     const SkImageInfo info = fBitmap.info();
     if ((kUnknown_SkColorType == info.colorType()) || !fBitmap.getPixels()) {
         return nullptr;
     }
     *infoPtr = info;
     *rowBytesPtr = fBitmap.rowBytes();
     return fBitmap.getPixels();
 }
 
-void SkImage_Raster::onPreroll(GrContext* ctx) const {
-    // SkImage can be called from lots of threads, but our fBitmap is *not* thread-safe,
-    // so we have to perform this lock/unlock in a non-racy way... we make a copy!
-    SkBitmap localShallowCopy(fBitmap);
-    localShallowCopy.lockPixels();
-    localShallowCopy.unlockPixels();
-}
-
 SkData* SkImage_Raster::onRefEncoded() const {
     SkPixelRef* pr = fBitmap.pixelRef();
     const SkImageInfo prInfo = pr->info();
     const SkImageInfo bmInfo = fBitmap.info();
 
     // we only try if we (the image) cover the entire area of the pixelRef
     if (prInfo.width() == bmInfo.width() && prInfo.height() == bmInfo.height()) {
         return pr->refEncodedData();
     }
     return nullptr;
@@ skipping 110 matching lines @@
     SkBitmap bitmap;
     if (!SkInstallDiscardablePixelRef(generator, subset, &bitmap, nullptr)) {
         return nullptr;
     }
     if (0 == bitmap.width() || 0 == bitmap.height()) {
         return nullptr;
     }
     return new SkImage_Raster(bitmap, nullptr);
 }
 #endif