Enable platform echo cancellation through the AudioRecord path.

media/base/android/java/src/org/chromium/media/AudioManagerAndroid.java

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.media;
 
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothManager;
 import android.content.BroadcastReceiver;
 import android.content.ContentResolver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.pm.PackageManager;
 import android.database.ContentObserver;
 import android.media.AudioFormat;
 import android.media.AudioManager;
 import android.media.AudioRecord;
 import android.media.AudioTrack;
+import android.media.audiofx.AcousticEchoCanceler;
 import android.os.Build;
 import android.os.Handler;
 import android.os.Looper;
 import android.os.Process;
 import android.provider.Settings;
 import android.util.Log;
 
 import org.chromium.base.CalledByNative;
 import org.chromium.base.JNINamespace;
 
@@ skipping 273 matching lines @@
                     i++;
                 }
             }
             logd("getAudioInputDeviceNames: " + devices);
             return array;
         }
     }
 
     @CalledByNative
     private int getNativeOutputSampleRate() {
-        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN_MR1) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
             String sampleRateString = mAudioManager.getProperty(
                     AudioManager.PROPERTY_OUTPUT_SAMPLE_RATE);
             return (sampleRateString == null ?
                     DEFAULT_SAMPLING_RATE : Integer.parseInt(sampleRateString));
         } else {
             return DEFAULT_SAMPLING_RATE;
         }
     }
 
   /**
@@ skipping 43 matching lines @@
     }
 
     @CalledByNative
     private int getAudioLowLatencyOutputFrameSize() {
         String framesPerBuffer =
                 mAudioManager.getProperty(AudioManager.PROPERTY_OUTPUT_FRAMES_PER_BUFFER);
         return (framesPerBuffer == null ?
                 DEFAULT_FRAME_PER_BUFFER : Integer.parseInt(framesPerBuffer));
     }
 
+    @CalledByNative
+    public static boolean shouldUseAcousticEchoCanceler() {
+        // AcousticEchoCanceler was added in API level 16 (Jelly Bean).
+        // Next is a list of device models which have been vetted for good
+        // quality platform echo cancellation.
+        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN &&
+               AcousticEchoCanceler.isAvailable() &&
+               (Build.MODEL.equals("Nexus 5") ||
+                Build.MODEL.equals("Nexus 7"));
+    }
+
     /** Sets the speaker phone mode. */
     public void setSpeakerphoneOn(boolean on) {
         boolean wasOn = mAudioManager.isSpeakerphoneOn();
         if (wasOn == on) {
             return;
         }
         mAudioManager.setSpeakerphoneOn(on);
     }
 
     /** Sets the microphone mute state. */
@@ skipping 204 matching lines @@
         }
     }
 
     private void logDeviceInfo() {
         Log.i(TAG, "Manufacturer:" + Build.MANUFACTURER +
                 " Board: " + Build.BOARD + " Device: " + Build.DEVICE +
                 " Model: " + Build.MODEL + " PRODUCT: " + Build.PRODUCT);
     }
 
     /** Trivial helper method for debug logging */
-    private void logd(String msg) {
+    private static void logd(String msg) {
         Log.d(TAG, msg);
     }
 
     /** Trivial helper method for error logging */
-    private void loge(String msg) {
+    private static void loge(String msg) {
         Log.e(TAG, msg);
     }
 
     private class SettingsObserver extends ContentObserver {
         SettingsObserver() {
             super(new Handler());
             mContentResolver.registerContentObserver(Settings.System.CONTENT_URI, true, this);
         }
 
         @Override
@@ skipping 19 matching lines @@
             synchronized (mSettingsObserverLock) {
                 mSettingsObserver = new SettingsObserver();
                 mSettingsObserverLock.notify();
             }
 
             // Listen for volume change.
             Looper.loop();
         }
     }
 }