Resetting media texture reference timer on update call to prevent purging from texture list while still in use. Keeping nullcheck just to be safe. (Broken video is preferable to a crash)

indra/newview/llviewermedia.cpp

@@ -989,6 +989,12 @@ void LLViewerMediaImpl::updateImagesMediaStreams()
 	
 	LLViewerMediaTexture* placeholder_image = (LLViewerMediaTexture*)LLViewerTextureManager::findTexture( mTextureId );
 	
+	if(!placeholder_image)
+	{
+		return NULL;
+	}
+	placeholder_image->getLastReferencedTimer()->reset();
+
 	if (mNeedsNewTexture 
 		|| placeholder_image->getUseMipMaps()
 		|| ! placeholder_image->mIsMediaTexture