- Don't pass the ShortcutService instance as an argument. This tiny
optimization is no longer meaningful now that PackageShortcut and
PackageLauncher have reference to ShortcutUser.
- Rename mLauncherComponent to mDefaultLauncherComponent for clarity.
- Don't instantiate ShortcutPackage instances when not needed.
- Don't allow intents with a null action.
- Also improve javadoc.
Bug 28592642
Bug 28474517
Bug 28557169
Change-Id: I8790d3494bf3b92c143c02824b0ed0e514504baa