Adding Chrome-side WebVR interface

content/public/android/java/src/org/chromium/content/browser/input/CardboardVRDevice.java

+// 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.
+
+package org.chromium.content.browser.input;
+
+import android.content.Context;
+
+import com.google.vrtoolkit.cardboard.CardboardDeviceParams;
+import com.google.vrtoolkit.cardboard.FieldOfView;
+import com.google.vrtoolkit.cardboard.HeadMountedDisplay;
+import com.google.vrtoolkit.cardboard.HeadMountedDisplayManager;
+import com.google.vrtoolkit.cardboard.ScreenParams;
+import com.google.vrtoolkit.cardboard.sensors.HeadTracker;

[mdempsky, 2015/05/11 22:11:09]

This appears to be a (publicly) undocumented part of the Cardboard API. If you
haven't already, it's probably worth pinging the Cardboard folks to make sure
they know you're using it like this.

+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+
+/**
+ * This is the implementation of the C++ counterpart CardboardVRDevice.
+ */
+@JNINamespace("content")
+class CardboardVRDevice {
+    private static final String TAG = "CardboardVRDevice";
+    private final HeadMountedDisplayManager mHMDManager;

[mdempsky, 2015/05/11 22:11:09]

According to the documentation and examples I can find, it looks you're supposed
to call onPause and onResume when the ambient Activity has been paused/resumed. 
But I don't see that happening here.

+    private final HeadTracker mHeadTracker;
+
+    @CalledByNative
+    private static CardboardVRDevice create(Context context) {
+        return new CardboardVRDevice(context);
+    }
+
+    private CardboardVRDevice(Context context) {
+        mHMDManager = new HeadMountedDisplayManager(context);
+
+        mHeadTracker = HeadTracker.createFromContext(context);
+        mHeadTracker.setNeckModelEnabled(true);
+        mHeadTracker.startTracking();
+    }
+
+    @CalledByNative
+    private void getFieldOfView(float[] outFov) {
+        HeadMountedDisplay hmd = mHMDManager.getHeadMountedDisplay();
+        CardboardDeviceParams deviceParams = hmd.getCardboardDeviceParams();
+        FieldOfView fov = deviceParams.getLeftEyeMaxFov();
+        outFov[0] = fov.getTop();
+        outFov[1] = fov.getBottom();
+        outFov[2] = fov.getLeft();
+        outFov[3] = fov.getRight();
+    }
+
+    @CalledByNative
+    private float getIpd() {
+        HeadMountedDisplay hmd = mHMDManager.getHeadMountedDisplay();
+        CardboardDeviceParams deviceParams = hmd.getCardboardDeviceParams();
+        return deviceParams.getInterLensDistance();
+    }
+
+    @CalledByNative
+    private String getDeviceName() {
+        HeadMountedDisplay hmd = mHMDManager.getHeadMountedDisplay();
+        CardboardDeviceParams deviceParams = hmd.getCardboardDeviceParams();
+        return deviceParams.getVendor() + " " + deviceParams.getModel();
+    }
+
+    @CalledByNative
+    private void getScreenSize(int[] outSize) {
+        HeadMountedDisplay hmd = mHMDManager.getHeadMountedDisplay();
+        ScreenParams screenParams = hmd.getScreenParams();
+        outSize[0] = screenParams.getWidth();
+        outSize[1] = screenParams.getHeight();
+    }
+
+    @CalledByNative
+    private void getSensorState(float[] outMatrix) {
+        mHeadTracker.getLastHeadView(outMatrix, 0);
+    }
+
+    @CalledByNative
+    private void stopTracking() {
+        mHeadTracker.stopTracking();
+    }
+
+    @CalledByNative
+    private void resetSensor() {
+        mHeadTracker.resetTracker();
+    }
+}