Move ClosePage() from RenderViewHost to WebContents.

extensions/browser/process_manager.cc

Index: extensions/browser/process_manager.cc
diff --git a/extensions/browser/process_manager.cc b/extensions/browser/process_manager.cc
index 47f7b191e004da8dccf2a6179c9a17a73471752f..d1908d2cd79155947f6e0cf7cffabe739a67f223 100644
--- a/extensions/browser/process_manager.cc
+++ b/extensions/browser/process_manager.cc
@@ -805,8 +805,8 @@ void ProcessManager::CloseLazyBackgroundPageNow(const std::string& extension_id,
       }
     }
     for (content::RenderFrameHost* frame : frames_to_close) {
-      frame->GetRenderViewHost()->ClosePage();
-      // RenderViewHost::ClosePage() may result in calling
+      content::WebContents::FromRenderFrameHost(frame)->ClosePage();
+      // WebContents::ClosePage() may result in calling
       // UnregisterRenderViewHost() asynchronously and may cause race conditions
       // when the background page is reloaded.
       // To avoid this, unregister the view now.