Enable removing uploads to evicted textures from texture upload queues.

cc/CCLayerTreeHost.h

Index: cc/CCLayerTreeHost.h
diff --git a/cc/CCLayerTreeHost.h b/cc/CCLayerTreeHost.h
index 4224c70612a687d5f84a37688c3bacaf1e368e94..9dd220fb906c65e756f830d07099ade8636a8dbe 100644
--- a/cc/CCLayerTreeHost.h
+++ b/cc/CCLayerTreeHost.h
@@ -194,6 +194,8 @@ public:
     // Delete contents textures' backing resources until they use only bytesLimit bytes. This may
     // be called on the impl thread while the main thread is running.
     void reduceContentsTexturesMemoryOnImplThread(size_t bytesLimit, CCResourceProvider*);
+    // Returns true if there any evicted backing textures that have not been deleted.
+    bool evictedContentsTexturesBackingsExist() const;
     // Retrieve the list of all contents textures' backings that have been evicted, to pass to the
     // main thread to unlink them from their owning textures.
     void getEvictedContentTexturesBackings(CCPrioritizedTextureManager::BackingVector&);