Purge cached resources on SkImage destruction.

src/core/SkBitmapProvider.cpp

Index: src/core/SkBitmapProvider.cpp
diff --git a/src/core/SkBitmapProvider.cpp b/src/core/SkBitmapProvider.cpp
index 96e29f81f2cd43aef74a3378ff7874fad35d1ced..cae744bcf04c0227f6bd9b23248c13c6b677b04b 100644
--- a/src/core/SkBitmapProvider.cpp
+++ b/src/core/SkBitmapProvider.cpp
@@ -62,7 +62,7 @@ SkBitmapCacheDesc SkBitmapProvider::makeCacheDesc() const {
 
 void SkBitmapProvider::notifyAddedToCache() const {
     if (fImage) {
-        // TODO

[tomhudson, 2015/09/18 13:30:54]

Looks like maybe this mattered but we let it fall through the cracks?

[mtklein, 2015/09/18 14:32:36]

Are we not DOing the TODO now?

+        as_IB(fImage)->notifyAddedToCache();

[tomhudson, 2015/09/18 13:30:54]

We're comfortable that this upcast is safe, that there aren't any other classes
derived from SkImage?

[f(malita), 2015/09/18 13:44:24]

Right:  SkImage_Base is the only derived class, and the motivation (IIUC) is to
hide internal implementation details from the public facing SkImage.  Within
Skia, we use as_IB(fImage) all over the place to access the private API.

     } else {
         fBitmap.pixelRef()->notifyAddedToCache();
     }