Introduce ChromeVR to Chrome on Android (behind a build flag)

chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShell.java

Index: chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShell.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShell.java b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShell.java
new file mode 100644
index 0000000000000000000000000000000000000000..6c4b688ad4e7c7059a26103ccd6224bdfc41e3b2
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShell.java
@@ -0,0 +1,159 @@
+// Copyright 2016 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.chrome.browser.vr_shell;
+
+import static android.opengl.GLES20.GL_NEAREST;
+import static android.opengl.GLES20.GL_TEXTURE_MAG_FILTER;
+import static android.opengl.GLES20.GL_TEXTURE_MIN_FILTER;
+import static android.opengl.GLES20.glBindTexture;
+import static android.opengl.GLES20.glGenTextures;
+import static android.opengl.GLES20.glTexParameteri;
+
+import android.app.Activity;
+import android.graphics.SurfaceTexture;
+import android.graphics.SurfaceTexture.OnFrameAvailableListener;
+import android.opengl.GLES11Ext;
+import android.opengl.GLSurfaceView;
+import android.view.MotionEvent;
+
+import com.google.vr.ndk.base.AndroidCompat;
+import com.google.vr.ndk.base.GvrLayout;
+
+import org.chromium.base.annotations.JNINamespace;
+
+import javax.microedition.khronos.egl.EGLConfig;
+import javax.microedition.khronos.opengles.GL10;
+
+/**
+ * This view extends from GvrLayout which wraps a GLSurfaceView that renders VR shell.
+ */
+@JNINamespace("vr_shell")
+public class VrShell extends GvrLayout implements GLSurfaceView.Renderer, OnFrameAvailableListener {
+    private Activity mActivity;
+
+    private GLSurfaceView mGlSurfaceView;
+
+    private SurfaceTexture mSurfaceTexture;
+
+    private long mNativeVrShell = 0;
+
+    public VrShell(Activity activity) {
+        super(activity);
+        mActivity = activity;
+    }
+
+    public void onNativeLibraryReady() {
+        mNativeVrShell = nativeInit();
+        mGlSurfaceView = new GLSurfaceView(getContext());
+        mGlSurfaceView.setEGLContextClientVersion(2);
+        mGlSurfaceView.setEGLConfigChooser(8, 8, 8, 0, 0, 0);
+        mGlSurfaceView.setPreserveEGLContextOnPause(true);
+        mGlSurfaceView.setRenderer(this);
+        setPresentationView(mGlSurfaceView);
+
+        if (setAsyncReprojectionEnabled(true)) {
+            AndroidCompat.setSustainedPerformanceMode(mActivity, true);
+        }
+    }
+
+    @Override
+    public void onFrameAvailable(SurfaceTexture surfaceTexture) {
+        mGlSurfaceView.queueEvent(new Runnable() {
+            @Override
+            public void run() {
+                try {
+                    mSurfaceTexture.updateTexImage();
+                } catch (IllegalStateException e) {
+                }
+            }
+        });
+    }
+
+    @Override
+    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
+        // This handle doesn't get deleted anywhere because we create it in onSurfaceCreated() and
+        // rely on onSurfaceDestroyed() according to the GLSurfaceView documentation to delete the
+        // context and clean up resources.
+        int textureDataHandle = createExternalTextureHandle();
+        mSurfaceTexture = new SurfaceTexture(textureDataHandle);
+        mSurfaceTexture.setOnFrameAvailableListener(this);
+        // TODO(bshe): Use this SurfaceTexture to create a Surface and then pass the Surface to a
+        // compositor to get frames of web page.
+        nativeGvrInit(mNativeVrShell, getGvrApi().getNativeGvrContext());
+        nativeInitializeGl(mNativeVrShell, textureDataHandle);
+    }
+
+    @Override
+    public void onSurfaceChanged(GL10 gl, int width, int height) {}
+
+    @Override
+    public boolean onTouchEvent(MotionEvent event) {
+        return false;
+    }
+
+    @Override
+    public void onDrawFrame(GL10 gl) {
+        nativeDrawFrame(mNativeVrShell);
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        if (mNativeVrShell != 0) {
+            nativeOnResume(mNativeVrShell);
+        }
+        AndroidCompat.setVrModeEnabled(mActivity, true);
+    }
+
+    @Override
+    public void onPause() {
+        super.onPause();
+        if (mNativeVrShell != 0) {
+            nativeOnPause(mNativeVrShell);
+        }
+    }
+
+    @Override
+    public void shutdown() {
+        super.shutdown();
+        if (mNativeVrShell != 0) {
+            nativeDestroy(mNativeVrShell);
+        }
+        if (mSurfaceTexture != null) {
+            mSurfaceTexture.release();
+        }
+    }
+
+    /**
+     * Create a new GLES11Ext.GL_TEXTURE_EXTERNAL_OES texture handle.
+     * @return New texture handle.
+     */
+    private int createExternalTextureHandle() {
+        int[] textureDataHandle = new int[1];
+        glGenTextures(1, textureDataHandle, 0);
+        if (textureDataHandle[0] != 0) {
+            glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, textureDataHandle[0]);
+            glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+            glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+            return textureDataHandle[0];
+        } else {
+            throw new RuntimeException("Error generating texture handle.");
+        }
+    }
+
+    private native long nativeInit();
+
+    private native void nativeGvrInit(long nativeVrShell, long nativeGvrApi);
+
+    private native void nativeDestroy(long nativeVrShell);
+
+    private native void nativeInitializeGl(long nativeVrShell, int textureDataHandle);
+
+    private native void nativeDrawFrame(long nativeVrShell);
+
+    private native void nativeOnPause(long nativeVrShell);
+
+    private native void nativeOnResume(long nativeVrShell);
+}