Support capturing back key events

Make CarInputManager capture KEYCODE_BACK as part of
INPUT_TYPE_NAVIGATE_KEYS.

Test: Manual - see comment #20 in the bug.
      Use `adb shell cmd car_service inject-key 4` on emulator
      Use button 4 on CAN rotary controller
Bug: 183424213
Merged-In: Iac4a5acd795d5185d0d8e17e5e416adff943f383
Change-Id: I109183d84d01d68cab30ef124803009a69f37db0
diff --git a/car-lib/src/android/car/input/CarInputManager.java b/car-lib/src/android/car/input/CarInputManager.java
index 7eddcf8..6f54c79 100644
--- a/car-lib/src/android/car/input/CarInputManager.java
+++ b/car-lib/src/android/car/input/CarInputManager.java
@@ -159,7 +159,7 @@
     public static final int INPUT_TYPE_DPAD_KEYS = 100;
 
     /**
-     * This is for all {@code KeyEvent#KEYCODE_NAVIGATE_*} keys.
+     * This is for all {@code KeyEvent#KEYCODE_NAVIGATE_*} keys and {@link KeyEvent#KEYCODE_BACK}.
      *
      * @hide
      */
diff --git a/service/src/com/android/car/InputCaptureClientController.java b/service/src/com/android/car/InputCaptureClientController.java
index 5f9ebfa..4e866a5 100644
--- a/service/src/com/android/car/InputCaptureClientController.java
+++ b/service/src/com/android/car/InputCaptureClientController.java
@@ -79,6 +79,7 @@
             entry(KeyEvent.KEYCODE_NAVIGATE_OUT, CarInputManager.INPUT_TYPE_NAVIGATE_KEYS),
             entry(KeyEvent.KEYCODE_NAVIGATE_NEXT, CarInputManager.INPUT_TYPE_NAVIGATE_KEYS),
             entry(KeyEvent.KEYCODE_NAVIGATE_PREVIOUS, CarInputManager.INPUT_TYPE_NAVIGATE_KEYS),
+            entry(KeyEvent.KEYCODE_BACK, CarInputManager.INPUT_TYPE_NAVIGATE_KEYS),
             entry(KeyEvent.KEYCODE_SYSTEM_NAVIGATION_DOWN,
                     CarInputManager.INPUT_TYPE_SYSTEM_NAVIGATE_KEYS),
             entry(KeyEvent.KEYCODE_SYSTEM_NAVIGATION_UP,