Add HDMI-CEC service

This CL adds a system service handling HDMI-CEC protocol. The service
is equipped with the capability sending/receiving HDMI-CEC messages

Not all the messages are in place. Currently it has messages to support
a few features only, as follows:

- One touch play
- System information
- Routing control (partially - active source status maintenance only)
- Device OSD transfer
- Power status

It will be extended to cover the wider usages in the follow up CLs.

The CEC standard version referenced in the implementation is 1.3a.

Change-Id: Ifed0b02f52ebf098eddb3bd0987efbf353b7e8fe
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index 05c9b17..317e307 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -682,6 +682,12 @@
         android:label="@string/permlab_installLocationProvider"
         android:description="@string/permdesc_installLocationProvider" />
 
+    <!-- Allows HDMI-CEC service to access device and configuration files.
+         @hide This should only be used by HDMI-CEC service.
+    -->
+    <permission android:name="android.permission.HDMI_CEC"
+        android:protectionLevel="signatureOrSystem" />
+
     <!-- Allows an application to use location features in hardware,
          such as the geofencing api.
          <p>Not for use by third-party applications. -->