Changing SpawnChild to return a struct.

base/android/java/src/org/chromium/base/ParcelableChannelServer.java

Index: base/android/java/src/org/chromium/base/ParcelableChannelServer.java
diff --git a/base/android/java/src/org/chromium/base/ParcelableChannelServer.java b/base/android/java/src/org/chromium/base/ParcelableChannelServer.java
new file mode 100644
index 0000000000000000000000000000000000000000..a12f4a59a3c00f03953756f5208bf6f852e08396
--- /dev/null
+++ b/base/android/java/src/org/chromium/base/ParcelableChannelServer.java
@@ -0,0 +1,64 @@
+// 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.base;
+
+import android.os.Parcelable;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.annotation.concurrent.GuardedBy;
+
+/**
+ * Provides an implementation of IParcelableChannel that stores the received parcelables and make
+ * them accessible to native code.
+ */
+@JNINamespace("base::android")
+public class ParcelableChannelServer extends IParcelableChannel.Stub {
+    private static final String TAG = "ParcelableChanServer";
+
+    private final String mName;
+    private final Object mLock = new Object();
+
+    @GuardedBy("mLock")
+    private final Map<Integer, Parcelable> mReceivedParcelables = new HashMap<>();
+
+    public ParcelableChannelServer(String name) {
+        mName = name;
+    }
+
+    public void clearReceivedParcelables() {
+        mReceivedParcelables.clear();
+    }
+
+    @Override
+    public void sendParcelable(ParcelableWrapper parcelableValue) {
+        synchronized (mLock) {
+            mReceivedParcelables.put(parcelableValue.getId(), parcelableValue.getParcelable());
+            mLock.notifyAll();
+        }
+    }
+
+    @CalledByNative
+    public Parcelable takeParcelable(int id) {
+        Parcelable parcelable = null;
+        synchronized (mLock) {
+            while (parcelable == null) {
+                parcelable = mReceivedParcelables.remove(id);
+                if (parcelable == null) {
+                    try {
+                        mLock.wait();
+                    } catch (InterruptedException ie) {
+                        Log.e(TAG, "Interrupted while waiting.", ie);
+                    }
+                }
+            }
+        }
+        return parcelable;
+    }
+}