внедрение $ http в угловой сервис usestrict

Попробуйте обернуть свою функцию внутри массива и объявить $ http как первый элемент этого массива, поэтому он выглядит так:

'use strict';

angular.module('bitsGantt')
    .service('Infoservice', ['$http', function Infoservice($http) {
        return {
            getSampleData: function() {
                // $http({
                //  method: 'GET',
                //  URL: 
                // })
                return [
                        // Order is optional. If not specified it will be assigned automatically
                        {name: 'Milestones', height: '3em', sortable: false, drawTask: false, classes: 'gantt-row-milestone', color: '#45607D', tasks: [
                            // Dates can be specified as string, timestamp or javascript date object. The data attribute can be used to attach a custom object
                            {name: 'Kickoff', color: '#93C47D', from: '2016-10-07T09:00:00', to: '2016-10-07T10:00:00', data: 'Can contain any custom data or object'},
                            {name: 'Concept approval', color: '#93C47D', from: new Date(2016, 9, 18, 18, 0, 0), to: new Date(2016, 9, 18, 18, 0, 0), est: new Date(2016, 9, 16, 7, 0, 0), lct: new Date(2016, 9, 19, 0, 0, 0)},
                            {name: 'Development finished', color: '#93C47D', from: new Date(2016, 10, 15, 18, 0, 0), to: new Date(2016, 10, 15, 18, 0, 0)},
                            {name: 'Shop is running', color: '#93C47D', from: new Date(2016, 10, 22, 12, 0, 0), to: new Date(2016, 10, 22, 12, 0, 0)},
                            {name: 'Go-live', color: '#93C47D', from: new Date(2016, 10, 29, 16, 0, 0), to: new Date(2016, 10, 29, 16, 0, 0)}
                        ], data: 'This here can contain any custom data, or even an object!'},
                        {name: 'Status meetings', tasks: [
                            {name: 'Bits Demo #1', color: '#9FC5F8', from: new Date(2016, 9, 25, 15, 0, 0), to: new Date(2016, 9, 25, 18, 30, 0)},
                            {name: 'Bits Demo #2', color: '#9FC5F8', from: new Date(2016, 10, 1, 15, 0, 0), to: new Date(2016, 10, 1, 18, 0, 0)},
                            {name: 'Bits Demo #3', color: '#9FC5F8', from: new Date(2016, 10, 8, 15, 0, 0), to: new Date(2016, 10, 8, 18, 0, 0)},
                            {name: 'Bits Demo #4', color: '#9FC5F8', from: new Date(2016, 10, 15, 15, 0, 0), to: new Date(2016, 10, 15, 18, 0, 0)},
                            {name: 'Bits Demo #5', color: '#9FC5F8', from: new Date(2016, 10, 24, 9, 0, 0), to: new Date(2016, 10, 24, 10, 0, 0)}
                        ]},
                        {name: 'Kickoff', movable: {allowResizing: false}, tasks: [
                            {name: 'Day 1', color: '#9FC5F8', from: new Date(2016, 9, 7, 9, 0, 0), to: new Date(2016, 9, 7, 17, 0, 0),
                                progress: {percent: 100, color: '#3C8CF8'}, movable: false},
                            {name: 'Day 2', color: '#9FC5F8', from: new Date(2016, 9, 8, 9, 0, 0), to: new Date(2016, 9, 8, 17, 0, 0),
                                progress: {percent: 100, color: '#3C8CF8'}},
                            {name: 'Day 3', color: '#9FC5F8', from: new Date(2016, 9, 9, 8, 30, 0), to: new Date(2016, 9, 9, 12, 0, 0),
                                progress: {percent: 100, color: '#3C8CF8'}}
                        ]},
                        {name: 'Create concept', tasks: [
                            {name: 'Create concept', priority: 20, content: '<i class="fa fa-cog" ng-click="scope.handleTaskIconClick(task.model)"></i> {{task.model.name}}', color: '#F1C232', from: new Date(2016, 9, 10, 8, 0, 0), to: new Date(2016, 9, 16, 18, 0, 0), est: new Date(2016, 9, 8, 8, 0, 0), lct: new Date(2016, 9, 18, 20, 0, 0),
                                progress: 100}
                        ]},
                        {name: 'Finalize concept', tasks: [
                            {id: 'Finalize concept', name: 'Finalize concept', priority: 10, color: '#F1C232', from: new Date(2016, 9, 17, 8, 0, 0), to: new Date(2016, 9, 18, 18, 0, 0),
                                progress: 100}
                        ]},
                        {name: 'Development', children: ['Sprint 1', 'Sprint 2', 'Sprint 3', 'Sprint 4'], content: '<i class="fa fa-file-code-o" ng-click="scope.handleRowIconClick(row.model)"></i> {{row.model.name}}'},
                        {name: 'Sprint 1', tooltips: false, tasks: [
                            {id: 'Product list view', name: 'Product list view', color: '#F1C232', from: new Date(2016, 9, 21, 8, 0, 0), to: new Date(2016, 9, 25, 15, 0, 0),
                                progress: 25, dependencies: [{to: 'Order basket'}, {from: 'Finalize concept'}]}
                        ]},
                        {name: 'Sprint 2', tasks: [
                            {id: 'Order basket', name: 'Order basket', color: '#F1C232', from: new Date(2016, 9, 28, 8, 0, 0), to: new Date(2016, 10, 1, 15, 0, 0),
                                dependencies: {to: 'Checkout'}}
                        ]},
                        {name: 'Sprint 3', tasks: [
                            {id: 'Checkout', name: 'Checkout', color: '#F1C232', from: new Date(2016, 10, 4, 8, 0, 0), to: new Date(2016, 10, 8, 15, 0, 0),
                                dependencies: {to: 'Login & Signup & Admin Views'}}
                        ]},
                        {name: 'Sprint 4', tasks: [
                            {id: 'Login & Signup & Admin Views', name: 'Login & Signup & Admin Views', color: '#F1C232', from: new Date(2016, 10, 11, 8, 0, 0), to: new Date(2016, 10, 15, 15, 0, 0),
                                dependencies: [{to: 'HW'}, {to: 'SW / DNS/ Backups'}]}
                        ]},
                        {name: 'Hosting'},
                        {name: 'Setup', tasks: [
                            {id: 'HW', name: 'HW', color: '#F1C232', from: new Date(2016, 10, 18, 8, 0, 0), to: new Date(2016, 10, 18, 12, 0, 0)}
                        ]},
                        {name: 'Config', tasks: [
                            {id: 'SW / DNS/ Backups', name: 'SW / DNS/ Backups', color: '#F1C232', from: new Date(2016, 10, 18, 12, 0, 0), to: new Date(2016, 10, 21, 18, 0, 0)}
                        ]},
                        {name: 'Server', parent: 'Hosting', children: ['Setup', 'Config']},
                        {name: 'Deployment', parent: 'Hosting', tasks: [
                            {name: 'Depl. & Final testing', color: '#F1C232', from: new Date(2016, 10, 21, 8, 0, 0), to: new Date(2016, 10, 22, 12, 0, 0), 'classes': 'gantt-task-deployment'}
                        ]},
                        {name: 'Workshop', tasks: [
                            {name: 'On-side education', color: '#F1C232', from: new Date(2016, 10, 24, 9, 0, 0), to: new Date(2016, 10, 25, 15, 0, 0)}
                        ]},
                        {name: 'Content', tasks: [
                            {name: 'Supervise content creation', color: '#F1C232', from: new Date(2016, 10, 26, 9, 0, 0), to: new Date(2016, 10, 29, 16, 0, 0)}
                        ]},
                        {name: 'Documentation', tasks: [
                            {name: 'Technical/User documentation', color: '#F1C232', from: new Date(2016, 10, 26, 8, 0, 0), to: new Date(2016, 10, 28, 18, 0, 0)}
                        ]}
                   //close of return
                    ];
           //close of function         
            },
            getSampleTimespans: function() {
                return [
                        {
                            from: new Date(2016, 9, 21, 8, 0, 0),
                            to: new Date(2016, 9, 25, 15, 0, 0),
                            name: 'Sprint 1 Timespan'
                            //priority: undefined,
                            //classes: [],
                            //data: undefined
                        }
                   //close of return     
                    ];
          //close of function          
            }]
      //close of main return      
        };
  //close of info service      
    })
;