Edit in JSFiddle

var myapp = angular.module('sampleapp', [ ]);

myapp.controller('samplecontoller', function ($scope) {

    $scope.labelList = [
	            {name:'India'},
	            {name:'USA'},
	            {name:'Russia'},
	            {name:'China'},
	            {name:'Australia'},
	            {name:'Japan'}
	        ]
    $scope.model = {
    	selectedLabelList : []
    }
    $scope.isSelectAll = function(){
    $scope.model.selectedLabelList = [];
		if($scope.master){
		$scope.master = true;
	    for(var i=0;i<$scope.labelList.length;i++){
						        $scope.model.selectedLabelList.push($scope.labelList[i].name);		
					}
				}
    else{$scope.master = false;}
   angular.forEach($scope.labelList, function (item) {
		    item.selected = $scope.master;
   });
}
    
  $scope.isLabelChecked = function()
			{
				var _name = this.label.name;
				if(this.label.selected){
					$scope.model.selectedLabelList.push(_name);
					if($scope.model.selectedLabelList.length == $scope.labelList.length ){$scope.master = true;}
				}else{
					$scope.master = false;
					var index = $scope.model.selectedLabelList.indexOf(_name);
					$scope.model.selectedLabelList.splice(index, 1);
				}
				
			}  
    
    
});

 

<div ng-app="sampleapp" ng-controller="samplecontoller">
<input type="checkbox" ng-model="master" ng-change="isSelectAll()"><label>Countries</label><br>
<span ng-repeat="label in labelList">
<input type="checkbox" ng-model="label.selected" ng-change="isLabelChecked()">
<label>{{ label.name }}</label>
</span>
 </div>

span{
    display:block;
    margin-left:10px;
}
label{
    display:inline-block !important;;
}
div{
    margin:10px 10px;
}
input{
    cursor:pointer;
    vertical-align:top;
}