Plumb Push API permission request through Blink using Frame.

Source/web/PushPermissionClientImpl.h

+// Copyright 2014 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.
+
+#ifndef PushPermissionClientImpl_h
+#define PushPermissionClientImpl_h
+
+#include "modules/push_messaging/PushPermissionClient.h"
+
+namespace blink {
+
+class PushPermissionClientImpl : public NoBaseWillBeGarbageCollectedFinalized<PushPermissionClientImpl>, public PushPermissionClient {
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(PushPermissionClientImpl);
+public:
+    static PassOwnPtrWillBeRawPtr<PushPermissionClientImpl> create();
+
+    ~PushPermissionClientImpl() override;
+
+    // PushPermissionClient implementation.
+    void requestPermission(ExecutionContext*, WebCallback*) override;
+
+    // NoBaseWillBeGarbageCollectedFinalized implementation.
+    void trace(Visitor* visitor) override { PushPermissionClient::trace(visitor); }
+
+private:
+    PushPermissionClientImpl();
+};
+
+} // namespace blink
+
+#endif // PushPermissionClientImpl_h