Enable platform echo cancellation through the AudioRecord path.

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

Index: media/base/android/java/src/org/chromium/media/AudioRecordInput.java
diff --git a/media/base/android/java/src/org/chromium/media/AudioRecordInput.java b/media/base/android/java/src/org/chromium/media/AudioRecordInput.java
index b629f527bd4e4c26c0ac329b2cd5b70a2b0a7361..dec4a37d1480d56c7d07ac0fc5f834c086712969 100644
--- a/media/base/android/java/src/org/chromium/media/AudioRecordInput.java
+++ b/media/base/android/java/src/org/chromium/media/AudioRecordInput.java
@@ -7,6 +7,9 @@ package org.chromium.media;
 import android.media.AudioFormat;
 import android.media.AudioRecord;
 import android.media.MediaRecorder.AudioSource;
+import android.media.audiofx.AcousticEchoCanceler;
+import android.media.audiofx.AudioEffect;
+import android.media.audiofx.AudioEffect.Descriptor;
 import android.os.Process;
 import android.util.Log;
 
@@ -20,6 +23,8 @@ import java.nio.ByteBuffer;
 @JNINamespace("media")
 class AudioRecordInput {
     private static final String TAG = "AudioRecordInput";
+    // Set to true to enable debug logs. Always check in as false.
+    private static final boolean DEBUG = false;
     // We are unable to obtain a precise measurement of the hardware delay on
     // Android. This is a conservative lower-bound based on measurments. It
     // could surely be tightened with further testing.
@@ -30,9 +35,11 @@ class AudioRecordInput {
     private final int mChannels;
     private final int mBitsPerSample;
     private final int mHardwareDelayBytes;
+    private final boolean mUsePlatformAEC;
     private ByteBuffer mBuffer;
     private AudioRecord mAudioRecord;
     private AudioRecordThread mAudioRecordThread;
+    private AcousticEchoCanceler mAEC;
 
     private class AudioRecordThread extends Thread {
         // The "volatile" synchronization technique is discussed here:
@@ -43,13 +50,7 @@ class AudioRecordInput {
 
         @Override
         public void run() {
-            try {
-                Process.setThreadPriority(Process.THREAD_PRIORITY_URGENT_AUDIO);
-            } catch (IllegalArgumentException e) {
-                Log.wtf(TAG, "setThreadPriority failed", e);
-            } catch (SecurityException e) {
-                Log.wtf(TAG, "setThreadPriority failed", e);
-            }
+            Process.setThreadPriority(Process.THREAD_PRIORITY_URGENT_AUDIO);
             try {
                 mAudioRecord.startRecording();
             } catch (IllegalStateException e) {
@@ -64,6 +65,11 @@ class AudioRecordInput {
                                  mHardwareDelayBytes);
                 } else {
                     Log.e(TAG, "read failed: " + bytesRead);
+                    if (bytesRead == AudioRecord.ERROR_INVALID_OPERATION) {
+                        // This can happen if there is already an active
+                        // AudioRecord (e.g. in another tab).
+                        mKeepAlive = false;
+                    }
                 }
             }
 
@@ -88,28 +94,26 @@ class AudioRecordInput {
 
     @CalledByNative
     private static AudioRecordInput createAudioRecordInput(long nativeAudioRecordInputStream,
-            int sampleRate, int channels, int bitsPerSample, int bytesPerBuffer) {
+            int sampleRate, int channels, int bitsPerSample, int bytesPerBuffer,
+            boolean usePlatformAEC) {
         return new AudioRecordInput(nativeAudioRecordInputStream, sampleRate, channels,
-                                    bitsPerSample, bytesPerBuffer);
+                                    bitsPerSample, bytesPerBuffer, usePlatformAEC);
     }
 
     private AudioRecordInput(long nativeAudioRecordInputStream, int sampleRate, int channels,
-                             int bitsPerSample, int bytesPerBuffer) {
+                             int bitsPerSample, int bytesPerBuffer, boolean usePlatformAEC) {
         mNativeAudioRecordInputStream = nativeAudioRecordInputStream;
         mSampleRate = sampleRate;
         mChannels = channels;
         mBitsPerSample = bitsPerSample;
         mHardwareDelayBytes = HARDWARE_DELAY_MS * sampleRate / 1000 * bitsPerSample / 8;
+        mUsePlatformAEC = usePlatformAEC;
 
         // We use a direct buffer so that the native class can have access to
         // the underlying memory address. This avoids the need to copy from a
         // jbyteArray to native memory. More discussion of this here:
         // http://developer.android.com/training/articles/perf-jni.html
-        try {
-            mBuffer = ByteBuffer.allocateDirect(bytesPerBuffer);
-        } catch (IllegalArgumentException e) {
-            Log.wtf(TAG, "allocateDirect failure", e);
-        }
+        mBuffer = ByteBuffer.allocateDirect(bytesPerBuffer);
         // Rather than passing the ByteBuffer with every OnData call (requiring
         // the potentially expensive GetDirectBufferAddress) we simply have the
         // the native class cache the address to the memory once.
@@ -170,6 +174,26 @@ class AudioRecordInput {
             return false;
         }
 
+        if (AcousticEchoCanceler.isAvailable()) {
+            mAEC = AcousticEchoCanceler.create(mAudioRecord.getAudioSessionId());
+            if (mAEC == null) {
+                Log.e(TAG, "AcousticEchoCanceler.create failed");
+                return false;
+            }
+            int ret = mAEC.setEnabled(mUsePlatformAEC);
+            if (ret != AudioEffect.SUCCESS) {
+                Log.e(TAG, "setEnabled error: " + ret);
+                return false;
+            }
+
+            if (DEBUG) {
+                Descriptor descriptor = mAEC.getDescriptor();
+                Log.d(TAG, "AcousticEchoCanceler " +
+                        "name: " + descriptor.name + ", " +
+                        "implementor: " + descriptor.implementor + ", " +
+                        "uuid: " + descriptor.uuid);
+            }
+        }
         return true;
     }
 
@@ -207,6 +231,11 @@ class AudioRecordInput {
             // open() was not called.
             return;
         }
+
+        if (mAEC != null) {
+            mAEC.release();
+            mAEC = null;
+        }
         mAudioRecord.release();
         mAudioRecord = null;
     }