fix a checked mode issues with preferences.dart
Bumped Chrome Platform Analytics to 1.5.2
Merge pull request #3509 from devoncarew/devoncarew_prefs_types

fix a checked mode issues with preferences.dart
Fix "JS Polymer element" template
Merge pull request #3512 from ussuri/fix-templates

Fix "JS Polymer element" template
Merge pull request #3510 from emilycodes/bump-chrome-platform-analytics

Bumped Chrome Platform Analytics to 1.5.2
Merge branch 'master' into git_salt_3
Rename common => GitSalt
Add git-salt dart interface
Load git-salt when flag enabled.