Implement SpeechRecognizerImplAndroid

content/public/android/java/src/org/chromium/content/browser/SpeechRecognition.java

Index: content/public/android/java/src/org/chromium/content/browser/SpeechRecognition.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/SpeechRecognition.java b/content/public/android/java/src/org/chromium/content/browser/SpeechRecognition.java
new file mode 100644
index 0000000000000000000000000000000000000000..f23064c05615634afeab5c2cb22541df4650187a
--- /dev/null
+++ b/content/public/android/java/src/org/chromium/content/browser/SpeechRecognition.java
@@ -0,0 +1,116 @@
+// Copyright (c) 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.content.browser;
+
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.speech.RecognitionListener;
+import android.speech.RecognizerIntent;
+import android.speech.SpeechRecognizer;
+import android.widget.Toast;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+import org.chromium.base.ThreadUtils;
+
+import java.util.ArrayList;
+import java.util.concurrent.FutureTask;
+
+/**
+ * Android speech recognition adapter.
+ */
+@JNINamespace("content")
+class SpeechRecognition {
+
+    private Intent intent = null;
+    private Context mContext = null;
+    private SpeechRecognizer recognizer = null;
+    private RecognitionListener listener = null;
+    private int mNativeSpeechRecognizerImplAndroid = 0;

[Primiano Tucci (use gerrit), 2013/06/03 16:24:11]

You'll need a reviewer for someone more experienced than me on this .java file
:).
Is this the right way to issue callbacks between Java and C++?

+
+    class Listener implements RecognitionListener {
+        @Override
+        public void onBeginningOfSpeech() {
+            nativeOnSoundStartJNI(mNativeSpeechRecognizerImplAndroid);
+        }
+        @Override

[Primiano Tucci (use gerrit), 2013/06/03 16:24:11]

Nit: \n? (here and below)

+        public void onBufferReceived(byte[] buffer) { }
+        @Override
+        public void onEndOfSpeech() {
+            nativeOnSoundEndJNI(mNativeSpeechRecognizerImplAndroid);
+        }
+        @Override
+        public void onError(int error) {
+            nativeOnRecognitionErrorJNI(mNativeSpeechRecognizerImplAndroid, error);
+        }
+        @Override
+        public void onEvent(int event, Bundle bundle) { }
+        @Override
+        public void onPartialResults(Bundle bundle) {
+            handleResults(bundle, true);
+        }
+        @Override
+        public void onReadyForSpeech(Bundle bundle) {
+            nativeOnAudioStartJNI(mNativeSpeechRecognizerImplAndroid);
+        }
+        @Override
+        public void onResults(Bundle bundle) {
+            handleResults(bundle, false);
+            // FIXME call recognizer.destroy() ?

[janx, 2013/05/31 17:22:24]

I am not sure when it makes the most sense to destroy the SpeechRecognizer.
After it has finished recognizing? When stopped? When cancelled?

[Primiano Tucci (use gerrit), 2013/06/03 16:24:11]

Just before calling the OnRecognitionEndJNI method sounds fine.
However, it's more important that you clean up the
mNativeSpeechRecognizerImplAndroid pointer and either check-for-null or assert
before calling JNI methods.

+        }
+        @Override
+        public void onRmsChanged(float rms) {
+            nativeOnAudioLevelsChangeJNI(mNativeSpeechRecognizerImplAndroid, rms);

[Primiano Tucci (use gerrit), 2013/06/03 16:24:11]

See my previous comments, I think you can remove completely this call and leave
onRmsChanged unimplemented.
Also, please can you add a TODO to speech_recognition_event_listener.h to the
OnAudioLevelsChange, mentioning that is just needed for x-webkit-speech bubble
support? Thanks

+        }
+        public void handleResults(Bundle bundle, boolean partial) {
+            ArrayList<String> results = bundle.getStringArrayList(SpeechRecognizer.RESULTS_RECOGNITION);
+            String[] strings = results.toArray(new String[results.size()]);

[Primiano Tucci (use gerrit), 2013/06/03 16:24:11]

s/strings/transcripts/

+            float[] floats = bundle.getFloatArray(SpeechRecognizer.CONFIDENCE_SCORES);

[Primiano Tucci (use gerrit), 2013/06/03 16:24:11]

s/floats/scores/

+            nativeOnRecognitionResultsJNI(mNativeSpeechRecognizerImplAndroid, strings, floats, partial);
+        }
+    }
+
+    private SpeechRecognition(final Context context, int nativeSpeechRecognizerImplAndroid) {
+        mContext = context;
+        mNativeSpeechRecognizerImplAndroid = nativeSpeechRecognizerImplAndroid;
+        listener = new Listener();
+        intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
+        recognizer = SpeechRecognizer.createSpeechRecognizer(mContext);
+        recognizer.setRecognitionListener(listener);
+    }
+
+    @CalledByNative
+    public static SpeechRecognition createSpeechRecognition(Context context, int nativeSpeechRecognizerImplAndroid) {
+        return new SpeechRecognition(context, nativeSpeechRecognizerImplAndroid);
+    }
+
+    @CalledByNative
+    public void StartRecognition(boolean continuous, boolean partial_results) {
+        // TODO(janx): Uncomment following line when the EXTRA is supported.
+        //intent.putExtra(RecognizerIntent.EXTRA_CONTINUOUS, continuous);
+        intent.putExtra(RecognizerIntent.EXTRA_PARTIAL_RESULTS, partial_results);
+        recognizer.startListening(intent);
+    }
+
+    @CalledByNative
+    public void CancelRecognition() {
+        recognizer.cancel();
+        // FIXME call recognizer.destroy() ?

[janx, 2013/05/31 17:22:24]

ditto

[Primiano Tucci (use gerrit), 2013/06/03 16:24:11]

As in my previous comment, s/CancelRecognition/AbortRecognition/.
You need to be sure here the the On...End events are always correctly
dispatched. The question is: will recognizer.cancel() cause further (Java)
callbacks on the listener? Maybe the onEndOfSpeech() event will?
In that case, you don't want to .destroy here().

+    }
+
+    @CalledByNative
+    public void StopRecognition() {
+        recognizer.stopListening();
+        // FIXME call recognizer.destroy() ?

[janx, 2013/05/31 17:22:24]

ditto

[Primiano Tucci (use gerrit), 2013/06/03 16:24:11]

Definitely not here. On StopRecognition we are interested in getting
(eventually) results with the audio captured so far.

+    }
+
+    private native void nativeOnAudioStartJNI(int nativeSpeechRecognizerImplAndroid);
+    private native void nativeOnSoundStartJNI(int nativeSpeechRecognizerImplAndroid);
+    private native void nativeOnSoundEndJNI(int nativeSpeechRecognizerImplAndroid);
+    private native void nativeOnRecognitionResultsJNI(int nativeSpeechRecognizerImplAndroid, String[] strings, float[] floats, boolean partial);
+    private native void nativeOnRecognitionErrorJNI(int nativeSpeechRecognizerImplAndroid, int error);
+    private native void nativeOnAudioLevelsChangeJNI(int nativeSpeechRecognizerImplAndroid, float rms);

[janx, 2013/05/31 17:22:24]

Those lines are more than 80 characters and the presubmit checks complain about
it, but the code looks really bad and confusing when wrapped, and other files in
the same folder ignore the 80 char limit. Should those lines be wrapped? If so,
how?

[Primiano Tucci (use gerrit), 2013/06/03 16:24:11]

I'm fine with no wrapping if there are other similar cases.

+}