use special-image for imagefilters and save/restore layer

src/image/SkImage_Base.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImage_Base_DEFINED
 #define SkImage_Base_DEFINED
 
@@ skipping 49 matching lines @@
     virtual bool onAsLegacyBitmap(SkBitmap*, LegacyBitmapMode) const;
 
     virtual bool onIsLazyGenerated() const { return false; }
 
     // Return a bitmap suitable for passing to image-filters
     // For now, that means wrapping textures into SkGrPixelRefs...
     virtual bool asBitmapForImageFilters(SkBitmap* bitmap) const {
         return this->getROPixels(bitmap, kAllow_CachingHint);
     }
 
+    virtual bool canBeImageFiltered() const {

[robertphillips, 2016/07/18 17:01:58]

Make this live ?

[reed1, 2016/07/18 22:06:07]

Done.

+        // bitmap.info().colorType() == kN32_SkColorType && !bitmap.info().gammaCloseToSRGB()
+        return true;
+    }
+
     // Call when this image is part of the key to a resourcecache entry. This allows the cache
     // to know automatically those entries can be purged when this SkImage deleted.
     void notifyAddedToCache() const {
         fAddedToCache.store(true);
     }
 
 private:
     // Set true by caches when they cache content that's derived from the current pixels.
     mutable SkAtomic<bool> fAddedToCache;
 
     typedef SkImage INHERITED;
 };
 
 static inline SkImage_Base* as_IB(SkImage* image) {
     return static_cast<SkImage_Base*>(image);
 }
 
 static inline SkImage_Base* as_IB(const sk_sp<SkImage>& image) {
     return static_cast<SkImage_Base*>(image.get());
 }
 
 static inline const SkImage_Base* as_IB(const SkImage* image) {
     return static_cast<const SkImage_Base*>(image);
 }
 
 #endif