SkImage_Raster's pixels are always immutable.

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 69 matching lines @@
 
     bool isOpaque() const override;
     bool onAsLegacyBitmap(SkBitmap*, LegacyBitmapMode) const override;
 
     SkImage_Raster(const SkBitmap& bm, const SkSurfaceProps* props, bool lockPixels = false)
         : INHERITED(bm.width(), bm.height(), props)
         , fBitmap(bm) {
         if (lockPixels) {
             fBitmap.lockPixels();
         }
+        SkASSERT(fBitmap.isImmutable());
     }
 
 private:
-    SkImage_Raster() : INHERITED(0, 0, NULL) {}
+    SkImage_Raster() : INHERITED(0, 0, NULL) {
+        fBitmap.setImmutable();
+    }
 
     SkBitmap    fBitmap;
 
     typedef SkImage_Base INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 static void release_data(void* addr, void* context) {
     SkData* data = static_cast<SkData*>(context);
@@ skipping 12 matching lines @@
     fBitmap.lockPixels();
 }
 
 SkImage_Raster::SkImage_Raster(const Info& info, SkPixelRef* pr, const SkIPoint& pixelRefOrigin,
                                size_t rowBytes,  const SkSurfaceProps* props)
     : INHERITED(info.width(), info.height(), props)
 {
     fBitmap.setInfo(info, rowBytes);
     fBitmap.setPixelRef(pr, pixelRefOrigin);
     fBitmap.lockPixels();
+    SkASSERT(fBitmap.isImmutable());
 }
 
 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);
 }
 
 SkSurface* SkImage_Raster::onNewSurface(const SkImageInfo& info, const SkSurfaceProps& props) const {
@@ skipping 89 matching lines @@
 
 SkImage* SkNewImageFromPixelRef(const SkImageInfo& info, SkPixelRef* pr,
                                 const SkIPoint& pixelRefOrigin, size_t rowBytes,
                                 const SkSurfaceProps* props) {
     if (!SkImage_Raster::ValidArgs(info, rowBytes, NULL, NULL)) {
         return NULL;
     }
     return SkNEW_ARGS(SkImage_Raster, (info, pr, pixelRefOrigin, rowBytes, props));
 }
 
-SkImage* SkNewImageFromRasterBitmap(const SkBitmap& bm, bool forceSharePixelRef,
-                                    const SkSurfaceProps* props, SharedPixelRefMode mode) {
+SkImage* SkNewImageFromRasterBitmap(const SkBitmap& bm, const SkSurfaceProps* props,
+                                    SharedPixelRefMode mode, ForceCopyMode forceCopy) {
     SkASSERT(NULL == bm.getTexture());
 
     if (!SkImage_Raster::ValidArgs(bm.info(), bm.rowBytes(), NULL, NULL)) {
         return NULL;
     }
 
     SkImage* image = NULL;
-    if (forceSharePixelRef || bm.isImmutable()) {
-        image = SkNEW_ARGS(SkImage_Raster, (bm, props, kLocked_SharedPixelRefMode == mode));
-    } else {
+    if (kYes_ForceCopyMode == forceCopy || !bm.isImmutable()) {
         SkBitmap tmp(bm);
         tmp.lockPixels();
         if (tmp.getPixels()) {
             image = SkImage::NewRasterCopy(tmp.info(), tmp.getPixels(), tmp.rowBytes(),
                                            tmp.getColorTable());
         }
 
         // we don't expose props to NewRasterCopy (need a private vers) so post-init it here
         if (image && props) {
             as_IB(image)->initWithProps(*props);
         }
+    } else {
+        image = SkNEW_ARGS(SkImage_Raster, (bm, props, kLocked_SharedPixelRefMode == mode));
     }
     return image;
 }
 
 const SkPixelRef* SkBitmapImageGetPixelRef(const SkImage* image) {
     return ((const SkImage_Raster*)image)->getPixelRef();
 }
 
 bool SkImage_Raster::isOpaque() const {
     return fBitmap.isOpaque();
 }
 
 bool SkImage_Raster::onAsLegacyBitmap(SkBitmap* bitmap, LegacyBitmapMode mode) const {
     if (kRO_LegacyBitmapMode == mode) {
         // When we're a snapshot from a surface, our bitmap may not be marked immutable
         // even though logically always we are, but in that case we can't physically share our
         // pixelref since the caller might call setImmutable() themselves
         // (thus changing our state).
         if (fBitmap.isImmutable()) {
             bitmap->setInfo(fBitmap.info(), fBitmap.rowBytes());
             bitmap->setPixelRef(fBitmap.pixelRef(), fBitmap.pixelRefOrigin());
             return true;
         }
     }
     return this->INHERITED::onAsLegacyBitmap(bitmap, mode);
 }