framework: Privacy Guard

 * Introduce a new privacy feature which allows the user to run an
   application with reduced visibility into his or her personal data.
 * Adds a per-application flag and simple API to determine if this flag
   is enabled for the current or calling process.
 * This flag can be used by content providers to decide if they should
   return a limited/empty dataset.

Change-Id: Id7c54d728e63acb2b02a2a9322930b54949f6c5d

Conflicts:
	core/java/android/app/ActivityManagerNative.java
	core/java/android/app/ApplicationPackageManager.java
	core/java/android/app/ContextImpl.java
	core/java/android/app/IActivityManager.java
	core/java/android/content/Context.java
	core/java/android/content/ContextWrapper.java
	core/java/android/content/pm/IPackageManager.aidl
	core/java/android/content/pm/PackageManager.java
	core/java/android/content/pm/PackageUserState.java
	core/res/AndroidManifest.xml
	core/res/res/values/symbols.xml
	services/java/com/android/server/am/ActivityManagerService.java
	services/java/com/android/server/pm/PackageManagerService.java
	services/java/com/android/server/pm/PackageSettingBase.java
	services/java/com/android/server/pm/Settings.java
	test-runner/src/android/test/mock/MockContext.java
	test-runner/src/android/test/mock/MockPackageManager.java
	tools/layoutlib/bridge/src/com/android/layoutlib/bridge/android/BridgeContext.java