Allow default dialer changes and phone account enable/disable via ADB

Add commands accessible via adb shell that can be used for CTS tests
without the need for adb root
*set-phone-account-enabled
*set-phone-account-disabled
*set-default-dialer
*get-default-dialer

Modify enablePhoneAccount/setDefaultDialer to indicate success.

Remove now unused functionality in ProtectedEnableAccountPreferenceActivity
and ProtectedChangeDefaultDialerActivity.

Bug: 21583012
Change-Id: I542d145cc969334c004b8344fbbb01f278256f9d
diff --git a/telecomm/java/com/android/internal/telecom/ITelecomService.aidl b/telecomm/java/com/android/internal/telecom/ITelecomService.aidl
index aa02021..ea6a74a 100644
--- a/telecomm/java/com/android/internal/telecom/ITelecomService.aidl
+++ b/telecomm/java/com/android/internal/telecom/ITelecomService.aidl
@@ -231,5 +231,10 @@
     /**
      * @see TelecomServiceImpl#enablePhoneAccount
      */
-    void enablePhoneAccount(in PhoneAccountHandle accountHandle, boolean isEnabled);
+    boolean enablePhoneAccount(in PhoneAccountHandle accountHandle, boolean isEnabled);
+
+    /**
+     * @see TelecomServiceImpl#setDefaultDialer
+     */
+    boolean setDefaultDialer(in String packageName);
 }