Cleanup: Do not pass a non-const ref in RequestDesktopNotificationPermission.

Review URL: https://codereview.chromium.org/296043014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@272670 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chrome_content_browser_client.cc

@@ -2029,7 +2029,7 @@ content::MediaObserver* ChromeContentBrowserClient::GetMediaObserver() {
 void ChromeContentBrowserClient::RequestDesktopNotificationPermission(
     const GURL& source_origin,
     content::RenderFrameHost* render_frame_host,
-    base::Closure& callback) {
+    const base::Closure& callback) {
 #if defined(ENABLE_NOTIFICATIONS)
   // Skip showing the infobar if the request comes from an extension, and that
   // extension has the 'notify' permission. (If the extension does not have the

chrome/browser/chrome_content_browser_client.h

@@ -200,7 +200,7 @@ class ChromeContentBrowserClient : public content::ContentBrowserClient {
   virtual void RequestDesktopNotificationPermission(
       const GURL& source_origin,
       content::RenderFrameHost* render_frame_host,
-      base::Closure& callback) OVERRIDE;
+      const base::Closure& callback) OVERRIDE;
   virtual blink::WebNotificationPresenter::Permission
       CheckDesktopNotificationPermission(
           const GURL& source_origin,

content/public/browser/content_browser_client.h

@@ -451,7 +451,7 @@ class CONTENT_EXPORT ContentBrowserClient {
   virtual void RequestDesktopNotificationPermission(
       const GURL& source_origin,
       RenderFrameHost* render_frame_host,
-      base::Closure& callback) {}
+      const base::Closure& callback) {}
 
   // Checks if the given page has permission to show desktop notifications.
   // This is called on the IO thread.