Make sure the default CSP is used for <webview> with PlzNavigate.

extensions/browser/extensions_browser_client.h

Index: extensions/browser/extensions_browser_client.h
diff --git a/extensions/browser/extensions_browser_client.h b/extensions/browser/extensions_browser_client.h
index c27ae730663b75f95d0985b78f29ba111fdff8ee..5ddbde70f6bb7e88071e2e6b119ebeed6427e785 100644
--- a/extensions/browser/extensions_browser_client.h
+++ b/extensions/browser/extensions_browser_client.h
@@ -52,6 +52,7 @@ class ExtensionHostDelegate;
 class ExtensionPrefsObserver;
 class ExtensionApiFrameIdMap;
 class ExtensionApiFrameIdMapHelper;
+class ExtensionNavigationUIData;
 class ExtensionSystem;
 class ExtensionSystemProvider;
 class ExtensionWebContentsObserver;
@@ -256,6 +257,9 @@ class ExtensionsBrowserClient {
   // Returns true if activity logging is enabled for the given |context|.
   virtual bool IsActivityLoggingEnabled(content::BrowserContext* context);
 
+  virtual ExtensionNavigationUIData* GetExtensionNavigationUIData(
+      net::URLRequest* request);
+
   // Returns a delegate that provides kiosk mode functionality.
   virtual KioskDelegate* GetKioskDelegate() = 0;