Allow GrGpuResources' unique keys to be changed.

src/gpu/SkGr.cpp

Index: src/gpu/SkGr.cpp
diff --git a/src/gpu/SkGr.cpp b/src/gpu/SkGr.cpp
index e353d41b0641e88e2557d396640a2f5080b1f203..e13c2c7adcd329bae458a0e0b0760099ac33eb33 100644
--- a/src/gpu/SkGr.cpp
+++ b/src/gpu/SkGr.cpp
@@ -180,7 +180,7 @@ static GrTexture* create_texture_for_bmp(GrContext* ctx,
     if (result && optionalKey.isValid()) {
         BitmapInvalidator* listener = SkNEW_ARGS(BitmapInvalidator, (optionalKey));
         pixelRefForInvalidationNotification->addGenIDChangeListener(listener);
-        SkAssertResult(ctx->addResourceToCache(optionalKey, result));
+        ctx->addResourceToCache(optionalKey, result);
     }
     return result;
 }