Move document-opening logic into ActionHandlers.

Add tests for:
    viewing
    previewing
    managing (apks and partial files)
    opening containers
    showing chooser

Fix issue where partial files weren't being managed correctly.

Change-Id: I1d62bcd0fd5262d6354f0ddc2327d3f0d22c1f3b
diff --git a/src/com/android/documentsui/NavigationViewManager.java b/src/com/android/documentsui/NavigationViewManager.java
index a95bf72..4f97111 100644
--- a/src/com/android/documentsui/NavigationViewManager.java
+++ b/src/com/android/documentsui/NavigationViewManager.java
@@ -130,6 +130,7 @@
     }
 
     interface Environment {
+        @Deprecated  // Use CommonAddones#getCurrentRoot
         RootInfo getCurrentRoot();
         String getDrawerTitle();
         @Deprecated  // Use CommonAddones#refreshCurrentRootAndDirectory