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

src/core/SkImageCacherator.cpp

Index: src/core/SkImageCacherator.cpp
diff --git a/src/core/SkImageCacherator.cpp b/src/core/SkImageCacherator.cpp
index bdcd64f56ddedd896ea6d3f5a66274d6f2468b0f..9b7cf25bf42f28c45241612c4cb5c8682adf8b52 100644
--- a/src/core/SkImageCacherator.cpp
+++ b/src/core/SkImageCacherator.cpp
@@ -70,6 +70,9 @@ static bool check_output_bitmap(const SkBitmap& bitmap, uint32_t expectedID) {
     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();
@@ -256,7 +259,7 @@ GrTexture* SkImageCacherator::lockAsTexture(GrContext* ctx, SkImageUsageType usa
 
     // 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