notify resource caches when pixelref genID goes stale

src/core/SkPixelRef.cpp

Index: src/core/SkPixelRef.cpp
diff --git a/src/core/SkPixelRef.cpp b/src/core/SkPixelRef.cpp
index f56298165cd67648276272f6667d9753c38b604e..a2638c9431777d7301aed5acc25ed037c70c21cb 100644
--- a/src/core/SkPixelRef.cpp
+++ b/src/core/SkPixelRef.cpp
@@ -5,6 +5,7 @@
  * found in the LICENSE file.
  */
 
+#include "SkBitmapCache.h"
 #include "SkPixelRef.h"
 #include "SkThread.h"
 
@@ -222,6 +223,7 @@ void SkPixelRef::addGenIDChangeListener(GenIDChangeListener* listener) {
     *fGenIDChangeListeners.append() = listener;
 }
 
+// we need to be called *before* the genID gets changed or zerod
 void SkPixelRef::callGenIDChangeListeners() {
     // We don't invalidate ourselves if we think another SkPixelRef is sharing our genID.
     if (fUniqueGenerationID) {
@@ -231,6 +233,15 @@ void SkPixelRef::callGenIDChangeListeners() {
     }
     // Listeners get at most one shot, so whether these triggered or not, blow them away.
     fGenIDChangeListeners.deleteAll();
+
+    // if fGenerationID is 0, then perhaps we never had one, and we are in the destructor
+    if (fGenerationID) {
+        // If the ResourceCache ever generalizes/standardizes on accessing the gen-id field,
+        // then it would be more efficient to roll these together, and only grab the mutex
+        // and fixing the resources once...
+        SkBitmapCache::NotifyGenIDStale(fGenerationID);
+        SkMipMapCache::NotifyGenIDStale(fGenerationID);
+    }
 }
 
 void SkPixelRef::notifyPixelsChanged() {