Revert "Revert of https://codereview.chromium.org/108773003/"

include/core/SkMallocPixelRef.h

Index: include/core/SkMallocPixelRef.h
diff --git a/include/core/SkMallocPixelRef.h b/include/core/SkMallocPixelRef.h
index 100a15d90abb4ca55b30aa9af47e5ce17f18fa67..5ef70d69bc8ea020c8f0cc902e02760e5ea44c85 100644
--- a/include/core/SkMallocPixelRef.h
+++ b/include/core/SkMallocPixelRef.h
@@ -17,33 +17,52 @@
 */
 class SkMallocPixelRef : public SkPixelRef {
 public:
-    /** Allocate the specified buffer for pixels. The memory is freed when the
-        last owner of this pixelref is gone. If addr is NULL, sk_malloc_throw()
-        is called to allocate it.
+    /**
+     *  Return a new SkMallocPixelRef with the provided pixel storage, rowBytes,
+     *  and optional colortable. The caller is responsible for managing the
+     *  lifetime of the pixel storage buffer, as the pixelref will not try
+     *  to delete the storage.
+     *
+     *  This pixelref will ref() the specified colortable (if not NULL).
+     *
+     *  Returns NULL on failure.
      */
-    SkMallocPixelRef(void* addr, size_t size, SkColorTable* ctable, bool ownPixels = true);
-    virtual ~SkMallocPixelRef();
+    static SkMallocPixelRef* NewDirect(const SkImageInfo&, void* addr,
+                                       size_t rowBytes, SkColorTable*);
+
+    /**
+     *  Return a new SkMallocPixelRef, automatically allocating storage for the
+     *  pixels. If rowBytes are 0, an optimal value will be chosen automatically.
+     *  If rowBytes is > 0, then it will be respected, or NULL will be returned
+     *  if rowBytes is invalid for the specified info.
+     *
+     *  This pixelref will ref() the specified colortable (if not NULL).
+     *
+     *  Returns NULL on failure.
+     */
+    static SkMallocPixelRef* NewAllocate(const SkImageInfo& info,
+                                         size_t rowBytes, SkColorTable*);
 
     void* getAddr() const { return fStorage; }
 
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkMallocPixelRef)
 
 protected:
-    // overrides from SkPixelRef
-    virtual void* onLockPixels(SkColorTable**);
-    virtual void onUnlockPixels();
-
-    SkMallocPixelRef(SkFlattenableReadBuffer& buffer);
+    virtual bool onNewLockPixels(LockRec*) SK_OVERRIDE;
+    virtual void onUnlockPixels() SK_OVERRIDE;
     virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
+    virtual size_t getAllocatedSizeInBytes() const SK_OVERRIDE;
 
-    // Returns the allocation size for the pixels
-    virtual size_t getAllocatedSizeInBytes() const SK_OVERRIDE { return fSize; }
+    SkMallocPixelRef(SkFlattenableReadBuffer& buffer);
+    SkMallocPixelRef(const SkImageInfo&, void* addr, size_t rb, SkColorTable*,
+                     bool ownsPixels);
+    virtual ~SkMallocPixelRef();
 
 private:
-    void*           fStorage;
-    size_t          fSize;
-    SkColorTable*   fCTable;
-    bool            fOwnPixels;
+    void*               fStorage;
+    SkColorTable*       fCTable;
+    size_t              fRB;
+    const bool          fOwnPixels;
 
     typedef SkPixelRef INHERITED;
 };