[blink] Unique pointers in Platform.h

chrome/renderer/chrome_content_renderer_client.h

Index: chrome/renderer/chrome_content_renderer_client.h
diff --git a/chrome/renderer/chrome_content_renderer_client.h b/chrome/renderer/chrome_content_renderer_client.h
index 5b8afbbf02121ef174fdefcffa4166dd025130a5..a2ed8773f94b742e2cc1dff68c00f40cdbf970fc 100644
--- a/chrome/renderer/chrome_content_renderer_client.h
+++ b/chrome/renderer/chrome_content_renderer_client.h
@@ -151,7 +151,7 @@ class ChromeContentRendererClient : public content::ContentRendererClient {
       const content::RenderFrame* render_frame,
       blink::WebPageVisibilityState* override_state) override;
   bool IsExternalPepperPlugin(const std::string& module_name) override;
-  blink::WebSpeechSynthesizer* OverrideSpeechSynthesizer(
+  std::unique_ptr<blink::WebSpeechSynthesizer> OverrideSpeechSynthesizer(
       blink::WebSpeechSynthesizerClient* client) override;
   bool ShouldReportDetailedMessageForSource(
       const base::string16& source) const override;