Remove WebPushClient, no longer used anywhere

This interface used to be referenced from blink::PushController
and implemented by content::PushMessagingClient, but now those
two classes are gone we can safely remove this unused API.

Bug: 939943
Change-Id: Id0cbf05091234f94fa69e0b65e1079d92afbdf30
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1631596
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#666289}

third_party/blink/public/BUILD.gn

@@ -149,7 +149,6 @@ source_set("blink_headers") {
     "platform/modules/mediastream/web_platform_media_stream_source.h",
     "platform/modules/mediastream/web_platform_media_stream_track.h",
     "platform/modules/mediastream/webrtc_uma_histograms.h",
-    "platform/modules/push_messaging/web_push_client.h",
     "platform/modules/push_messaging/web_push_error.h",
     "platform/modules/push_messaging/web_push_subscription.h",
     "platform/modules/remoteplayback/web_remote_playback_client.h",

third_party/blink/public/platform/modules/push_messaging/web_push_client.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 THIRD_PARTY_BLINK_PUBLIC_PLATFORM_MODULES_PUSH_MESSAGING_WEB_PUSH_CLIENT_H_
-#define THIRD_PARTY_BLINK_PUBLIC_PLATFORM_MODULES_PUSH_MESSAGING_WEB_PUSH_CLIENT_H_
-
-#include <memory>
-#include "third_party/blink/public/platform/modules/push_messaging/web_push_error.h"
-#include "third_party/blink/public/platform/modules/push_messaging/web_push_subscription.h"
-#include "third_party/blink/public/platform/web_callbacks.h"
-
-namespace blink {
-
-struct WebPushSubscriptionOptions;
-
-class WebPushClient {
- public:
-  virtual ~WebPushClient() = default;
-
-  // Ownership of the callbacks is transferred to the client.
-  virtual void Subscribe(int64_t service_worker_registration_id,
-                         const WebPushSubscriptionOptions&,
-                         bool user_gesture,
-                         std::unique_ptr<WebPushSubscriptionCallbacks>) = 0;
-};
-
-}  // namespace blink
-
-#endif  // THIRD_PARTY_BLINK_PUBLIC_PLATFORM_MODULES_PUSH_MESSAGING_WEB_PUSH_CLIENT_H_

third_party/blink/public/web/web_local_frame_client.h

@@ -109,7 +109,6 @@ class WebMediaPlayerSource;
 class WebNavigationControl;
 class WebServiceWorkerProvider;
 class WebPlugin;
-class WebPushClient;
 class WebRTCPeerConnectionHandler;
 class WebRelatedAppsFetcher;
 class WebSocketHandshakeThrottle;
@@ -535,11 +534,6 @@ class BLINK_EXPORT WebLocalFrameClient {
   // Called to abort a navigation that is being handled by the browser process.
   virtual void AbortClientNavigation() {}
 
-  // Push API ---------------------------------------------------
-
-  // Used to access the embedder for the Push API.
-  virtual WebPushClient* PushClient() { return nullptr; }
-
   // InstalledApp API ----------------------------------------------------
 
   // Used to access the embedder for the InstalledApp API.