[Web MIDI] Use Android MIDI API.

media/midi/midi_input_port_android.cc

+// Copyright 2015 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.
+
+#include "media/midi/midi_input_port_android.h"
+
+#include "base/android/jni_array.h"
+#include "base/time/time.h"
+#include "jni/MidiInputPortAndroid_jni.h"
+
+namespace media {
+namespace midi {
+
+MidiInputPortAndroid::MidiInputPortAndroid(JNIEnv* env,
+                                           jobject raw,
+                                           Delegate* delegate)
+    : raw_port_(env, raw), delegate_(delegate) {}
+
+MidiInputPortAndroid::~MidiInputPortAndroid() {
+  Close();
+}
+
+bool MidiInputPortAndroid::Open() {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  return Java_MidiInputPortAndroid_open(env, raw_port_.obj(),
+                                        reinterpret_cast<jlong>(this));
+}
+
+void MidiInputPortAndroid::Close() {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  Java_MidiInputPortAndroid_close(env, raw_port_.obj());
+}
+
+void MidiInputPortAndroid::OnData(JNIEnv* env,
+                                  jobject caller,
+                                  jbyteArray data,
+                                  jint offset,
+                                  jint size,
+                                  jlong timestamp) {
+  std::vector<uint8> bytes;
+  base::android::JavaByteArrayToByteVector(env, data, &bytes);
+
+  if (size == 0) {
+    return;
+  }
+
+  // TimeTick's internal value is in microseconds, |timestamp| is in
+  // nanoseconds,

[Takashi Toyoshima, 2015/09/07 16:42:20]

Maybe "// nanoseconds. Both are monotonic."

[yhirano, 2015/09/10 11:43:50]

Done.

+  // both are monotonic.
+  base::TimeTicks timestamp_to_pass = base::TimeTicks::FromInternalValue(
+      timestamp / base::TimeTicks::kNanosecondsPerMicrosecond);
+  delegate_->OnReceivedData(this, &bytes[offset], size, timestamp_to_pass);
+}
+
+bool MidiInputPortAndroid::Register(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace midi
+}  // namespace media