Enable platform echo cancellation through the AudioRecord path.

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

Index: media/base/android/java/src/org/chromium/media/AudioManagerAndroid.java
diff --git a/media/base/android/java/src/org/chromium/media/AudioManagerAndroid.java b/media/base/android/java/src/org/chromium/media/AudioManagerAndroid.java
index 0c37c0a9e3a51c92e52e907ba449fcc76cd7019b..ee95b63aa942e1fb3cdada4346589fa20e1081f3 100644
--- a/media/base/android/java/src/org/chromium/media/AudioManagerAndroid.java
+++ b/media/base/android/java/src/org/chromium/media/AudioManagerAndroid.java
@@ -13,6 +13,7 @@ import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.pm.PackageManager;
 import android.database.ContentObserver;
+import android.media.audiofx.AcousticEchoCanceler;
 import android.media.AudioFormat;
 import android.media.AudioManager;
 import android.media.AudioRecord;
@@ -111,6 +112,14 @@ class AudioManagerAndroid {
     // fails.
     private static final int DEFAULT_FRAME_PER_BUFFER = 256;
 
+    // List of device models which have been vetted for good quality platform
+    // echo cancellation.
+    private static final Set<String> PLATFORM_AEC_MODEL_WHITELIST =

[henrika (OOO until Aug 14), 2013/12/06 22:51:57]

Just FYI, I was once told that every byte counts, especially on mobile
platforms, and we all know that HashSets is a rather new invention which we can
live without. Your choice.

[ajm, 2013/12/10 06:37:16]

Thanks, removed it.

+            new HashSet<String>(Arrays.asList(new String[] {
+                "Nexus 5",
+                "Nexus 7"
+            }));
+
     private final AudioManager mAudioManager;
     private final Context mContext;
     private final long mNativeAudioManagerAndroid;
@@ -314,7 +323,7 @@ class AudioManagerAndroid {
 
     @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 ?
@@ -378,6 +387,20 @@ class AudioManagerAndroid {
                 DEFAULT_FRAME_PER_BUFFER : Integer.parseInt(framesPerBuffer));
     }
 
+    @CalledByNative
+    public static boolean isPlatformAECSupported() {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
+            // AcousticEchoCanceler was added in API level 16 (Jelly Bean).
+            return false;
+        }
+
+        boolean isAvailable = AcousticEchoCanceler.isAvailable();
+        boolean isWhitelisted = PLATFORM_AEC_MODEL_WHITELIST.contains(Build.MODEL);
+        logd("AcousticEchoCanceler.isAvailable: " + isAvailable);
+        logd("Build.MODEL: " + Build.MODEL + " isWhitelisted: " + isWhitelisted);
+        return isAvailable && isWhitelisted;
+    }
+
     /** Sets the speaker phone mode. */
     public void setSpeakerphoneOn(boolean on) {
         boolean wasOn = mAudioManager.isSpeakerphoneOn();
@@ -603,12 +626,12 @@ class AudioManagerAndroid {
     }
 
     /** 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);
     }