Allow independent control of the back and the other navigation buttons.

Bug: 3363046
Change-Id: Icc312fc9ffbf2f584dc541489c9769b07ed50315
diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index 75791d5..fc0039e 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -1793,6 +1793,8 @@
      *
      * Flag to hide only the navigation buttons.  Don't use this
      * unless you're a special part of the system UI (i.e., setup wizard, keyguard).
+     *
+     * THIS DOES NOT DISABLE THE BACK BUTTON
      */
     public static final int STATUS_BAR_DISABLE_NAVIGATION = 0x00200000;
 
@@ -1802,10 +1804,22 @@
      * NOTE: This flag may only be used in subtreeSystemUiVisibility. It is masked
      * out of the public fields to keep the undefined bits out of the developer's way.
      *
+     * Flag to hide only the back button.  Don't use this
+     * unless you're a special part of the system UI (i.e., setup wizard, keyguard).
+     */
+    public static final int STATUS_BAR_DISABLE_BACK = 0x00400000;
+
+    /**
+     * @hide
+     *
+     * NOTE: This flag may only be used in subtreeSystemUiVisibility. It is masked
+     * out of the public fields to keep the undefined bits out of the developer's way.
+     *
      * Flag to hide only the clock.  You might use this if your activity has
      * its own clock making the status bar's clock redundant.
      */
-    public static final int STATUS_BAR_DISABLE_CLOCK = 0x00400000;
+    public static final int STATUS_BAR_DISABLE_CLOCK = 0x00800000;
+
 
     /**
      * @hide