Making callbacks in Android ChildProcessLauncher generic.

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

+// Copyright 2017 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.view.Surface;
+
+import org.chromium.base.UnguessableToken;
+import org.chromium.base.annotations.JNINamespace;
+import org.chromium.content.common.IGpuProcessCallback;
+import org.chromium.content.common.SurfaceWrapper;
+
+@JNINamespace("content")
+class GpuProcessCallback extends IGpuProcessCallback.Stub {
+    GpuProcessCallback() {}
+
+    @Override
+    public void forwardSurfaceForSurfaceRequest(UnguessableToken requestToken, Surface surface) {
+        nativeCompleteScopedSurfaceRequest(requestToken, surface);
+    }
+
+    @Override
+    public SurfaceWrapper getViewSurface(int surfaceId) {
+        Surface surface = nativeGetViewSurface(surfaceId);
+        if (surface == null) {
+            return null;
+        }
+        return new SurfaceWrapper(surface);
+    }
+
+    private static native void nativeCompleteScopedSurfaceRequest(
+            UnguessableToken requestToken, Surface surface);
+    private static native Surface nativeGetViewSurface(int surfaceId);
+};