PS - Showing permission prompt for activeTab

chrome/browser/chromeos/extensions/public_session_permission_helper.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_CHROMEOS_EXTENSIONS_PUBLIC_SESSION_PERMISSION_HELPER_H_
 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_PUBLIC_SESSION_PERMISSION_HELPER_H_
 
 #include <memory>
 #include <set>
 
@@ skipping 19 matching lines @@
 
 // In Public Sessions, extensions (and apps) are force-installed by admin policy
 // so the user does not get a chance to review the permissions for these
 // extensions. This is not acceptable from a security/privacy standpoint, so
 // when an extension uses one of the sensitive APIs for the first time, we show
 // the user a dialog where they can choose whether to allow the extension access
 // to the API.
 //
 // This function sets up the prompt asking the user for additional
 // permission(s), handles the result, caches it, and then runs the callback with
-// the allowed permissions as the argument.
+// the allowed permissions as the argument. It returns true if this
+// permission(s) is already resolved, and false otherwise.
 //
 // The user will be prompted about a certain permission only once, and that
 // choice will be cached and used in any subsequent requests that use the same
 // permission. If a request comes for a permission that is currently being
 // prompted, its callback will be queued up to be invoked when the prompt is
 // resolved.
 //
 // Caller must ensure that web_contents is valid. Must be called on UI thread.
 //
+// Callback can be null (permission_helper::RequestResolvedCallback()).

[Andrew T Wilson (Slow), 2017/05/09 13:29:29]

What does it mean if it's null? Does it still prompt (but doesn't invoke the
callback when the prompt is interacted with)?

[Ivan Šandrk, 2017/05/10 10:01:28]

Updated comment. And both correct - prompts but doesn't invoke the callback.

+//
 // Passing in a null prompt_factory (permission_helper::PromptFactory())
 // callback gets the default behaviour (ie. it is is used only for tests).
-void HandlePermissionRequest(const Extension& extension,
+bool HandlePermissionRequest(const Extension& extension,
                              const PermissionIDSet& requested_permissions,
                              content::WebContents* web_contents,
                              const RequestResolvedCallback& callback,
                              const PromptFactory& prompt_factory);
 
+// Returns true if user granted this permission to the extension.
+bool PermissionAllowed(const Extension* extension,
+                       APIPermission::ID permission);
+
 // Used to completely reset state in between tests.
 void ResetPermissionsForTesting();
 
 }  // namespace permission_helper
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_PUBLIC_SESSION_PERMISSION_HELPER_H_