2473 [Closed Captioning] Create SubRip file parser and dart closed caption data object (cla: yes)

2474 [in_app_purchase] Remove unused method from example app (cla: yes)

2475 Bump roboelectric version (cla: yes)

2476 Add missing Xcode workspaces to examples (cla: yes)

2477 [shared_preferences] fix typo in readme (cla: yes)

2481 [In_app_purchases] Removing extra testing changes for in-app-purchase example (cla: yes)

2482 [android_alarm_manager] Added Espresso test for background execution (cla: yes)

2483 [video_player, video_player_web] PlatformException fix (cla: yes, waiting for test harness)