optimize the disable-caching case for SkImage::readPixels

src/core/SkImageCacherator.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImageCacherator_DEFINED
 #define SkImageCacherator_DEFINED
 
@@ skipping 39 matching lines @@
      */
     GrTexture* lockAsTexture(GrContext*, const GrTextureParams&, const SkImage* client,
                              SkImage::CachingHint = SkImage::kAllow_CachingHint);
 
     /**
      *  If the underlying src naturally is represented by an encoded blob (in SkData), this returns
      *  a ref to that data. If not, it returns null.
      */
     SkData* refEncoded();
 
+    // Only return true if the generate has already been cached.
+    bool lockAsBitmapOnlyIfAlreadyCached(SkBitmap*);
+    // Call the underlying generator directly
+    bool directGeneratePixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRB,

[f(malita), 2015/11/24 19:36:07]

I guess this matches existing internal APIs, but would it make sense to switch
to SkPixmap at some point?

[reed1, 2015/11/24 19:43:49]

Yep. Would probably start with SkImageGenerator, and move our way up. I propose
we tackle that separately (thank goodness this header is private).

+                              int srcX, int srcY);
+
 private:
     SkImageCacherator(SkImageGenerator*, const SkImageInfo&, const SkIPoint&, uint32_t uniqueID);
 
     bool generateBitmap(SkBitmap*);
     bool tryLockAsBitmap(SkBitmap*, const SkImage*, SkImage::CachingHint);
 #if SK_SUPPORT_GPU
     // Returns the texture. If the cacherator is generating the texture and wants to cache it,
     // it should use the passed in key (if the key is valid).
     GrTexture* lockTexture(GrContext*, const GrUniqueKey& key, const SkImage* client,
                            SkImage::CachingHint);
@@ skipping 16 matching lines @@
     SkAutoTDelete<SkImageGenerator> fNotThreadSafeGenerator;
 
     const SkImageInfo   fInfo;
     const SkIPoint      fOrigin;
     const uint32_t      fUniqueID;
 
     friend class Cacherator_GrTextureMaker;
 };
 
 #endif