Revert of [blink] Unique pointers in Platform.h

chrome/renderer/chrome_content_renderer_client.h

 // Copyright (c) 2012 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 CHROME_RENDERER_CHROME_CONTENT_RENDERER_CLIENT_H_
 #define CHROME_RENDERER_CHROME_CONTENT_RENDERER_CLIENT_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 133 matching lines @@
   bool IsPrefetchOnly(content::RenderFrame* render_frame,
                       const blink::WebURLRequest& request) override;
   unsigned long long VisitedLinkHash(const char* canonical_url,
                                      size_t length) override;
   bool IsLinkVisited(unsigned long long link_hash) override;
   blink::WebPrescientNetworking* GetPrescientNetworking() override;
   bool ShouldOverridePageVisibilityState(
       const content::RenderFrame* render_frame,
       blink::WebPageVisibilityState* override_state) override;
   bool IsExternalPepperPlugin(const std::string& module_name) override;
-  std::unique_ptr<blink::WebSpeechSynthesizer> OverrideSpeechSynthesizer(
+  blink::WebSpeechSynthesizer* OverrideSpeechSynthesizer(
       blink::WebSpeechSynthesizerClient* client) override;
   bool ShouldReportDetailedMessageForSource(
       const base::string16& source) const override;
   bool ShouldGatherSiteIsolationStats() const override;
   blink::WebWorkerContentSettingsClientProxy*
   CreateWorkerContentSettingsClientProxy(content::RenderFrame* render_frame,
                                          blink::WebFrame* frame) override;
   bool AllowPepperMediaStreamAPI(const GURL& url) override;
   void AddSupportedKeySystems(
       std::vector<std::unique_ptr<::media::KeySystemProperties>>* key_systems)
@@ skipping 105 matching lines @@
   // Observes module load and unload events and notifies the ModuleDatabase in
   // the browser process.
   std::unique_ptr<ModuleWatcher> module_watcher_;
   mojom::ModuleEventSinkPtr module_event_sink_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ChromeContentRendererClient);
 };
 
 #endif  // CHROME_RENDERER_CHROME_CONTENT_RENDERER_CLIENT_H_