be sure to use cached bitmap when we need to upload something to make a texture

src/core/SkImageCacherator.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkBitmapCache.h"
 #include "SkImageCacherator.h"
@@ skipping 52 matching lines @@
     return generator->refEncodedData();
 }
 
 static bool check_output_bitmap(const SkBitmap& bitmap, uint32_t expectedID) {
     SkASSERT(bitmap.getGenerationID() == expectedID);
     SkASSERT(bitmap.isImmutable());
     SkASSERT(bitmap.getPixels());
     return true;
 }
 
+// Note, this returns a new, mutable, bitmap, with a new genID.
+// If you want the immutable bitmap with the same ID as our cacherator, call tryLockAsBitmap()

[tomhudson, 2015/09/14 17:31:45]

Is there some way we could change the names of these functions to make the very
different semantics clearer? Or are there Skia naming conventions documented
somewhere that would clue us in to this difference?

(Could we put a comment about a critical difference like this INTO THE HEADER,
which is what I'll be reading if I'm trying to figure out how to use the class?)

+//
 bool SkImageCacherator::generateBitmap(SkBitmap* bitmap) {
     ScopedGenerator generator(this);
     const SkImageInfo& genInfo = generator->getInfo();
     if (fInfo.dimensions() == genInfo.dimensions()) {
         SkASSERT(fOrigin.x() == 0 && fOrigin.y() == 0);
         // fast-case, no copy needed
         return generator->tryGenerateBitmap(bitmap, fInfo);
     } else {
         // need to handle subsetting, so we first generate the full size version, and then
         // "read" from it to get our subset. See skbug.com/4213
@@ skipping 166 matching lines @@
         ScopedGenerator generator(this);
         Generator_GrYUVProvider provider(generator);
         GrTexture* tex = provider.refAsTexture(ctx, desc, true);
         if (tex) {
             return set_key_and_return(tex, key);
         }
     }
 
     // 5. Ask the generator to return RGB(A) data, which the GPU can convert
     SkBitmap bitmap;
-    if (this->generateBitmap(&bitmap)) {
+    if (this->tryLockAsBitmap(&bitmap)) {
         return GrRefCachedBitmapTexture(ctx, bitmap, usage);
     }
 #endif
 
     return nullptr;
 }