Changing the icon of a list button in InboxSDK

content.js

InboxSDK.load('1.0', 'app-id').then(function(sdk){
	var threadDataManager = new ThreadDataManager();
		  sdk.Lists.registerThreadRowViewHandler(threadRowView => {
		    var threadID = threadRowView.getThreadID();
		    threadDataManager.setThreadData(threadID, chrome.runtime.getURL('images/logo1.png'));
		    threadRowView.addButton(
		      threadDataManager.getThreadStream(threadID)
                    .toProperty(() => threadDataManager.getThreadData(threadID))
                    .map(threadData => {
                    	console.log("thread data: ", threadData)
                      if(!threadData){
                        return null;
                      }
                      else{
                        return {
                          iconUrl: threadDataManager.getThreadData(threadID),
                          iconClass: '',
                          onClick: (event) => {
                          		console.log("thread data changing");
                          		threadDataManager.setThreadData(threadID, chrome.runtime.getURL('images/logo2.jpg'))
                          	console.log("clicked: ", threadDataManager.getThreadData(threadID))
                          },
                          hasDropdown: false
                        }; 
                      }
                    })
		    );
		  });
});

threadDataManager.js

class ThreadDataManager {
  constructor(){
    var self = this;
    this._emitter;
    this._stream = Kefir.stream(emitter => {
      self._emitter = emitter; 
      return () => null
    });
    this._stream.onAny(event => {
      console.log('Stream event:', event);
    });
    this._threadData = {}; //map from threadID to thread data
  }
  
  setThreadData(threadID, data){
    console.log("setting data for ", threadID, " to: ", data)
    this._threadData[threadID] = data;
    this._emitter.emit({threadID, data});
  }
  
  getThreadData(threadID){
    return this._threadData[threadID];
  }
  
  getThreadStream(threadID){
    console.log(this._emitter)
    return this._stream.filter(event => event.threadID === threadID);
  }
}