Remove PushPermissionClient.

Source/web/PushPermissionClientImpl.h

Index: Source/web/PushPermissionClientImpl.h
diff --git a/Source/web/PushPermissionClientImpl.h b/Source/web/PushPermissionClientImpl.h
deleted file mode 100644
index f71220ef64e26897b444b1f86f3917a6fca90bd5..0000000000000000000000000000000000000000
--- a/Source/web/PushPermissionClientImpl.h
+++ /dev/null
@@ -1,31 +0,0 @@
-// 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