fix images in multi-thread by doing shallow-copies

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 "SkImagePriv.h"
 #include "SkBitmap.h"
@@ skipping 113 matching lines @@
 }
 
 SkImage_Raster::~SkImage_Raster() {}
 
 SkShader* SkImage_Raster::onNewShader(SkShader::TileMode tileX, SkShader::TileMode tileY,
                                       const SkMatrix* localMatrix) const {
     return SkShader::CreateBitmapShader(fBitmap, tileX, tileY, localMatrix);
 }
 
 void SkImage_Raster::onDraw(SkCanvas* canvas, SkScalar x, SkScalar y, const SkPaint* paint) const {
-    canvas->drawBitmap(fBitmap, x, y, paint);
+    SkBitmap shallowCopy(fBitmap);
+    canvas->drawBitmap(shallowCopy, x, y, paint);
 }
 
 void SkImage_Raster::onDrawRect(SkCanvas* canvas, const SkRect* src, const SkRect& dst,
                                       const SkPaint* paint) const {
-    canvas->drawBitmapRectToRect(fBitmap, src, dst, paint);
+    SkBitmap shallowCopy(fBitmap);
+    canvas->drawBitmapRectToRect(shallowCopy, src, dst, paint);
 }
 
 SkSurface* SkImage_Raster::onNewSurface(const SkImageInfo& info, const SkSurfaceProps& props) const {
     return SkSurface::NewRaster(info, &props);
 }
 
 bool SkImage_Raster::onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
                                   int srcX, int srcY) const {
-    return fBitmap.readPixels(dstInfo, dstPixels, dstRowBytes, srcX, srcY);
+    SkBitmap shallowCopy(fBitmap);
+    return shallowCopy.readPixels(dstInfo, dstPixels, dstRowBytes, srcX, srcY);
 }
 
 const void* SkImage_Raster::onPeekPixels(SkImageInfo* infoPtr, size_t* rowBytesPtr) const {
     const SkImageInfo info = fBitmap.info();
     if ((kUnknown_SkColorType == info.colorType()) || !fBitmap.getPixels()) {
         return NULL;
     }
     *infoPtr = info;
     *rowBytesPtr = fBitmap.rowBytes();
     return fBitmap.getPixels();
@@ skipping 58 matching lines @@
     return SkNEW_ARGS(SkImage_Raster, (info, pr, rowBytes, props));
 }
 
 const SkPixelRef* SkBitmapImageGetPixelRef(const SkImage* image) {
     return ((const SkImage_Raster*)image)->getPixelRef();
 }
 
 bool SkImage_Raster::isOpaque() const {
     return fBitmap.isOpaque();
 }