Upstream: Renderers are running in WebAPKs.

chrome/android/webapk/libs/common/src/org/chromium/webapk/lib/common/WebApkSandboxedProcessService.java

+// 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.webapk.lib.common;
+
+import android.app.Service;
+import android.content.Context;
+import android.content.Intent;
+import android.os.IBinder;
+import android.util.Log;
+
+import dalvik.system.BaseDexClassLoader;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+/**
+ * Child process service hosted by WebAPKs. This class uses BaseDexClassLoader to load Chrome's
+ * {@link ChildProcessServiceImpl} which loads Chrome's native libraries, initializes JNI and
+ * creates renderer processes.
+ */
+public class WebApkSandboxedProcessService extends Service {
+    private static final String CHILD_PROCESS_SERVICE_IMPL =
+            "org.chromium.content.app.ChildProcessServiceImpl";
+    private static final String TAG = "cr_WebApkSandboxedProcessService";
+
+    private Class<?> mChildProcessServiceImplClass;
+    private Object mChildProcessServiceImplInstance;
+    private static ClassLoader sClassLoader;
+
+    /**
+     * Gets/creates ClassLoader for loading {@link CHILD_PROCESS_SERVICE_IMPL}.
+     * @param context WebAPK's context.
+     * @return The ClassLoader.
+     */
+    private static ClassLoader getClassLoaderInstance(Context context) {
+        if (sClassLoader == null) {
+            sClassLoader = createClassLoader(context);
+        }
+        return sClassLoader;
+    }
+
+    /**
+     * Creates ClassLoader for loading {@link CHILD_PROCESS_SERVICE_IMPL}.
+     * @param context WebAPK's context.
+     * @return The ClassLoader.
+     */
+    private static ClassLoader createClassLoader(Context context) {
+        Context remoteContext = WebApkUtils.getHostBrowserContext(context);
+        String dexPath = remoteContext.getApplicationInfo().sourceDir;
+        String libraryPath = remoteContext.getApplicationInfo().nativeLibraryDir;
+        return new BaseDexClassLoader(dexPath, null, libraryPath,
+                ClassLoader.getSystemClassLoader());

[pkotwicz, 2016/06/10 21:29:47]

can you instead return remoteContext.getClassLoader() ?
Can you remove the ClassLoader parameter from ChildProcessServiceImpl#create()?

[Xi Han, 2016/06/13 20:04:10]

It works! Updated the ChildProcessServiceImpl#create() as well.

+    }
+
+    @Override
+    public void onCreate() {
+        super.onCreate();
+
+        try {
+            BaseDexClassLoader classLoader = (BaseDexClassLoader) getClassLoaderInstance(
+                    getApplicationContext());

[pkotwicz, 2016/06/10 21:29:47]

Can the |classLoader| variable be of type ClassLoader instead of being of type
BaseDexClassLoader?

[Xi Han, 2016/06/13 20:04:11]

Done.

+            mChildProcessServiceImplClass =
+                    classLoader.loadClass(CHILD_PROCESS_SERVICE_IMPL);

[pkotwicz, 2016/06/10 21:29:47]

Nit: Can you call mChildProcessServiceImplClass.newInstance() ?

[Xi Han, 2016/06/13 20:04:10]

Thanks for catching this. I forgot to remove the constructor after removing the
parameter in the constructor function. The newInstance() call is enough.

+            Constructor<?> childProcessServiceImplConstructor =
+                    mChildProcessServiceImplClass.getConstructor();
+            mChildProcessServiceImplInstance = childProcessServiceImplConstructor.newInstance();

[pkotwicz, 2016/06/10 21:29:47]

Nit: mChildProcessServiceImplClass.newInstance()

[Xi Han, 2016/06/13 20:04:10]

Done.

+
+            Method createMethod = mChildProcessServiceImplClass.getMethod("create",
+                    Context.class, Context.class, ClassLoader.class);
+            createMethod.invoke(mChildProcessServiceImplInstance, getApplicationContext(),
+                    WebApkUtils.getHostBrowserContext(getApplicationContext()), classLoader);
+        } catch (Exception e) {
+            Log.d(TAG, "Unable to create a ChildProcessServiceImpl for the WebAPK.");
+            e.printStackTrace();
+        }
+    }
+
+    @Override
+    public IBinder onBind(Intent intent) {
+        // We call stopSelf() to request that this service be stopped as soon as the client
+        // unbinds. Otherwise the system may keep it around and available for a reconnect. The
+        // child processes do not currently support reconnect; they must be initialized from
+        // scratch every time.
+        stopSelf();
+        try {
+            Method bindMethod = mChildProcessServiceImplClass.getMethod(
+                    "bind", Intent.class);
+            return (IBinder) bindMethod.invoke(mChildProcessServiceImplInstance, intent);
+        } catch (NoSuchMethodException | IllegalAccessException | IllegalArgumentException

[pkotwicz, 2016/06/10 21:29:47]

Nit: Can you replace this with catch (Exception e) { ... } ?

[Xi Han, 2016/06/13 20:04:10]

Done.

+                | InvocationTargetException e) {
+            Log.d(TAG, "Unable to bind to the WebApkSandboxedProcessService.");
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        try {
+            Method destroyMethod = mChildProcessServiceImplClass.getMethod("destroy");
+            destroyMethod.invoke(mChildProcessServiceImplInstance);
+        } catch (NoSuchMethodException | IllegalAccessException | IllegalArgumentException
+                | InvocationTargetException e) {

[pkotwicz, 2016/06/10 21:29:47]

Nit: Can you replace this with catch (Exception e) { ... } ?

[Xi Han, 2016/06/13 20:04:10]

Done.

+            Log.d(TAG, "Unable to destroy the WebApkSandboxedProcessService.");
+            e.printStackTrace();
+        }
+    }
+}