Add a policy_browsertest for the DefaultWebBluetoothGuardSetting.

content/public/browser/content_browser_client.h

Index: content/public/browser/content_browser_client.h
diff --git a/content/public/browser/content_browser_client.h b/content/public/browser/content_browser_client.h
index 9e6c1745d80d750c65cfa8fbc47d39881ce421e7..5e67780483df2eb806ddc168f262078c1099268c 100644
--- a/content/public/browser/content_browser_client.h
+++ b/content/public/browser/content_browser_client.h
@@ -410,6 +410,11 @@ class CONTENT_EXPORT ContentBrowserClient {
   // Allow the embedder to control whether we can use <keygen>.
   virtual bool AllowKeygen(const GURL& url, content::ResourceContext* context);
 
+  // Allow the embedder to control whether we can use Web Bluetooth.
+  // TODO(https://crbug.com/563724): Replace this with a proper use of the
+  // permissions system.
+  virtual bool AllowWebBluetooth();
+
   // Allow the embedder to override the request context based on the URL for
   // certain operations, like cookie access. Returns nullptr to indicate the
   // regular request context should be used.