Implement KEYCODE_TV_POWER

For devices that are not Android TV devices and not connected to a TV via HDMI, KEYCODE_TV_POWER is ignored.
For the following Android TV devices, KEYCODE_TV_POWER is an alias of KEYCODE_POWER:
- Devices that don't support HDMI
- HDMI TV panel devices
- HDMI devices with POWER_CONTROL_MODE set to NONE
- HDMI devices with CEC control disabled
For all other HDMI devices, KEYCODE_TV_POWER is forwarded to the HDMI stack by calling toggleAndFollowTvPower(). For HDMI source devices, this results in
1. Toggling of the HDMI-connected TV power state over HDMI-CEC
2. The source device following the TV power state

Bug: 157402294
Test: adb shell input keyevent KEYCODE_TV_POWER, manually verified TV power toggle behavior on ADT3

Change-Id: I59cd3f2a5c2b7a551176ab40ef9c559ad502a974

1 files changed, 7 insertions, 2 deletions

diff --git a/core/java/android/view/KeyEvent.java b/core/java/android/view/KeyEvent.java
index c87e51e35891..37f0a64df613 100644
--- a/core/java/android/view/KeyEvent.java
+++ b/core/java/android/view/KeyEvent.java
@@ -519,8 +519,13 @@ public class KeyEvent extends InputEvent implements Parcelable {
     /** Key code constant: Settings key.
      * Starts the system settings activity. */
     public static final int KEYCODE_SETTINGS        = 176;
-    /** Key code constant: TV power key.
-     * On TV remotes, toggles the power on a television screen. */
+    /**
+     * Key code constant: TV power key.
+     * On HDMI TV panel devices and Android TV devices that don't support HDMI, toggles the power
+     * state of the device.
+     * On HDMI source devices, toggles the power state of the HDMI-connected TV via HDMI-CEC and
+     * makes the source device follow this power state.
+     */
     public static final int KEYCODE_TV_POWER        = 177;
     /** Key code constant: TV input key.
      * On TV remotes, switches the input on a television screen. */