old_contents: chrome.runtime.onInstalled.addListener(function(details) {
  	var status = null;
  	
  	try {
  		status = JSON.parse( localStorage.status );
  	} catch( e ) {
  		status = {};
  	}
  	
  	localStorage.status = JSON.stringify(
  		_.extend(
  			{
  				create: true,
  				delete: true,
  				fork: true,
  				issues_closed: true,
  				issues_comment: true,
  				issues_opened: true,
  				member_add: true,
  				push: true,
  				star: true
  			},
  			status
  		)
  	);
  });
  
  function insertCSS(name, type){
  	chrome.tabs.query({
  		url: 'https://github.com/'
  	}, function(tabs){
  		_.each(tabs, function( tab ){
  			try {
  				chrome.tabs.insertCSS(tab.id, {
  					file: '/chrome/github_css/' + name + '/' + type + '.css'
  				}, function(){
  				});
  			} catch(e) {
  				//cancel
  			}
  		});
  	});
  }
  
  chrome.runtime.onMessage.addListener(function(message, sender, sendResponse){
  	var action = message.action;
  
  	switch(action){
  		case 'insertCss':
  			var cssStatus = localStorage.status;
  
  			try {
  				cssStatus = JSON.parse(cssStatus);
  			} catch(e) {
  				cssStatus = {};
  			}
  
  			if(Object.keys(cssStatus).length > 0){
  				insertCSS('_all_', 'hide');
  			}
  
  			for(var i in cssStatus){
  				if(cssStatus[i]){
  					insertCSS(i, 'show');
  				} else {
  					insertCSS(i, 'hide');
  				}
  			}
  
  			sendResponse({
  				success: true
  			});
  			break;
  		default:
  			sendResponse({
  				success: true
  			});
  	}
  });
  
new_contents: chrome.runtime.onInstalled.addListener(function(details) {
  	var status = null;
  	
  	try {
  		status = JSON.parse( localStorage.status );
  	} catch( e ) {
  		status = {};
  	}
  	
  	localStorage.status = JSON.stringify(
  		_.extend(
  			{
  				create: true,
  				delete: true,
  				fork: true,
  				issues_closed: true,
  				issues_comment: true,
  				issues_opened: true,
  				member_add: true,
  				push: true,
  				star: true
  			},
  			status
  		)
  	);
  });
  
  function insertCSS(name, type){
  	chrome.tabs.query({
  		active: true
  	}, function(tabs){
  		_.each(tabs, function( tab ){
  			try {
  				chrome.tabs.insertCSS(tab.id, {
  					file: '/chrome/github_css/' + name + '/' + type + '.css'
  				}, function(){
  				});
  			} catch(e) {
  				//cancel
  			}
  		});
  	});
  }
  
  chrome.runtime.onMessage.addListener(function(message, sender, sendResponse){
  	var action = message.action;
  
  	switch(action){
  		case 'insertCss':
  			var cssStatus = localStorage.status;
  
  			try {
  				cssStatus = JSON.parse(cssStatus);
  			} catch(e) {
  				cssStatus = {};
  			}
  
  			if(Object.keys(cssStatus).length > 0){
  				insertCSS('_all_', 'hide');
  			}
  
  			for(var i in cssStatus){
  				if(cssStatus[i]){
  					insertCSS(i, 'show');
  				} else {
  					insertCSS(i, 'hide');
  				}
  			}
  
  			sendResponse({
  				success: true
  			});
  			break;
  		default:
  			sendResponse({
  				success: true
  			});
  	}
  });
  
subject: Use { active: true } instead of specified url