Add audio mode and audio focus support to Telecomm

This CL adds support for:
  - audio focus
  - switching to speaker phone
  - mute
  - wired headset

Bluetooth support is coming in a different CL.

Change-Id: Iaf4013ea747548451cff45b48bcbb5b1dd1b8498
diff --git a/src/com/android/telecomm/WiredHeadsetManager.java b/src/com/android/telecomm/WiredHeadsetManager.java
new file mode 100644
index 0000000..329df71
--- /dev/null
+++ b/src/com/android/telecomm/WiredHeadsetManager.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.telecomm;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.media.AudioManager;
+
+/**
+ * Listens for and caches headset state.  Used By the CallAudioManger for maintaining
+ * overall audio state for use in the UI layer. Also provides method for connecting the bluetooth
+ * headset to the phone call.
+ */
+class WiredHeadsetManager {
+    /** Receiver for wired headset plugged and unplugged events. */
+    private class WiredHeadsetBroadcastReceiver extends BroadcastReceiver {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            if (intent.getAction().equals(Intent.ACTION_HEADSET_PLUG)) {
+                boolean isPluggedIn = intent.getIntExtra("state", 0) == 1;
+                Log.v(WiredHeadsetManager.this, "ACTION_HEADSET_PLUG event, plugged in: %b",
+                        isPluggedIn);
+                onHeadsetPluggedInChanged(isPluggedIn);
+            }
+        }
+    }
+
+    private final CallAudioManager mCallAudioManager;
+    private final WiredHeadsetBroadcastReceiver mReceiver;
+    private boolean mIsPluggedIn;
+
+    WiredHeadsetManager(CallAudioManager callAudioManager) {
+        mCallAudioManager = callAudioManager;
+        mReceiver = new WiredHeadsetBroadcastReceiver();
+
+        Context context = TelecommApp.getInstance();
+        AudioManager audioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
+        mIsPluggedIn = audioManager.isWiredHeadsetOn();
+
+        // Register for misc other intent broadcasts.
+        IntentFilter intentFilter = new IntentFilter(Intent.ACTION_HEADSET_PLUG);
+        context.registerReceiver(mReceiver, intentFilter);
+    }
+
+    boolean isPluggedIn() {
+        return mIsPluggedIn;
+    }
+
+    private void onHeadsetPluggedInChanged(boolean isPluggedIn) {
+        if (mIsPluggedIn != isPluggedIn) {
+            Log.v(this, "onHeadsetPluggedInChanged, mIsPluggedIn: %b -> %b", mIsPluggedIn,
+                    isPluggedIn);
+            boolean oldIsPluggedIn = mIsPluggedIn;
+            mIsPluggedIn = isPluggedIn;
+            mCallAudioManager.onHeadsetPluggedInChanged(oldIsPluggedIn, mIsPluggedIn);
+        }
+    }
+}