[simple_browser] Refactored WebPageBloc to be more test-friendly.
- Separated fidl dependent codes from webpage_bloc.dart to services/simple_browser_web_servce.dart.
- Created a separate class SimpleBrowserNavigationEventListener that inherits fidl's NavigationEventListener so that it can be independently tested from SimpleBrowserWebService.
- Modified all files and tests affected by the refactoring.
- Changed the callback function '_handleAction' to '_onActionChanged' so that it sounds more like conventional callback name.
Change-Id: I1c84ca70ae44a22a9b18e8048ac66ee503b0a102
6 files changed
