The PermissionController is the entry point for clients of the permissions infrastructure from both the //content and the embedder (e.g. //chrome) layers. PermissionController provides access to the permissions API and can be reached as content::BrowserContext::GetPermissionController() or Profile::GetPermissionController().
PermissionController has the following API:
blink::mojom::PermissionStatus PermissionController::GetPermissionStatusForWorkerblink::mojom::PermissionStatus PermissionController::GetPermissionStatusForCurrentDocumentblink::mojom::PermissionStatus PermissionController::GetPermissionStatusForOriginWithoutContext Use this API only in special cases when there is no active document or worker. E.g., PermissionType::PAYMENT_HANDLER permission verification of payment providers in a PWA's manifest.PermissionController::RequestPermissionFromCurrentDocumentPermissionController::RequestPermissionsFromCurrentDocumentThe PermissionControllerImpl is the implementation of the PermissionController. PermissionControllerImpl is meant to be used only internally in //content and is not available for external clients.
PermissionControllerImpl provides various functionality such as:
The PermissionManager is an implementation of PermissionControllerDelegate. PermissionManager is a KeyedService which means it is attached to a BrowserContext. It allows to get permission status for ContentSettingsType. That API should be used only to display permission status in UI like PageInfo and SiteSettings.
Internally, PermissionManager holds a list of PermissionsContexts, one per ContentSettingType. PermissionContextBase is the base class for these contexts, and for every ContentSettingsType there is a specific ...PermissionsContext subclass.
EXAMPLE: NotificationPermissionContext handles the “NOTIFICATIONS” content setting.
In order to query, set, and reset the state of a permission, the HostContentSettingsMap KeyedService is used, which internally handles the more complicated things related to Content Settings.
In order to present the user with a permission prompt when a permission is requested, PermissionRequestManager is used.
In order to determine whether a permission is granted, blocked, needs a user decision, etc, the appropriate content setting is checked. Content settings are saved and retrieved using a key consisting of a 3-tuple of values:
A ContentSettingsPattern is basically a URL where every part (scheme, host port, path) is allowed to be either Wildcard or a specified value. Any other form or regex is not supported.
A key that has Wildcard for both the primary and secondary patterns represents the “Default” value for a specific ContentSettingsType. This is the least specific content setting that will match anything and serves as a backup for when no more-specific setting has been set.
When setting or retrieving a content setting, the HostContentSettingsMap uses a list of registered providers. This enum is sorted from highest priority to lowest. If a provider is able to handle a specific operation it will do so and the following providers are ignored, otherwise the next provider is queried and so on.
The underlying storage mechanism is provider-dependent.
The PermissionRequestManager facilitates making permission requests via AddRequest(). Only one request prompt is allowed to be in progress at a time, the manager holds a deque of pending requests for all requests that are kept waiting until the current prompt is resolved.
The PermissionRequestManager is attached and scoped to the lifetime of a WebContents. When the WebContents object is destroyed all current and queued requests are finalized as “IGNORED”.
It is possible to have more than one request be tied in to the same prompt. This only happens when the requests are allowed to be grouped together and they all requested one after another. Currently this is only the case for the Camera and Microphone permissions which can be grouped into one Camera+Microphone prompt.
--deny-permission-prompts command line switch will cause all permissions to be automatically denied.If the request has not been automatically resolved, it is added to deque of queued_requests_ from which it will be picked up as appropriate.
When a trigger causes the DequeueRequestIfNeeded function to be called it will check if the necessary conditions are met to show a new permission prompt and it will trigger showing the prompt. The conditions are:
DequeueRequestIfNeeded is triggered when:
When the prompt needs to be shown to the user, a platform specific subclass of PermissionPrompt is created which handles the creation and lifetime of the UI element and will report user actions back to the PermissionRequestManager.
The PermissionPrompt is responsible for deciding the exact UI surface and text to present to the user based on information about the request.
For specific permission prompt requests a decision could be made to enforce a quiet UI version of the permission prompt. Currently this only applies to NOTIFICATIONS permission requests.
A quiet UI prompt can be triggered if any of these conditions are met:
The ContextualNotificationPermissionUiSelector checks if the quiet UI is enabled in settings (among other things) when choosing the appropriate UI flavor.
A quiet UI prompt will use a right-side omnibox indicator on desktop or a mini-infobar on Android.
Requesting and verification of permissions does not feature unified behavior in different environments. In other words, based on the preconditions, a permission request could be shown or automatically declined. To make sure that all cases work as intended, we introduced PermissionsSecurityModelInteractiveUITest.
If you're adding a new environment that requires non-default behavior for permissions, then you need to add a test in PermissionsSecurityModelInteractiveUITest.
Steps to follow:
VerifyPermissionForXYZ, where XYZ is the name of your environment. You can use the already defined VerifyPermission method if you expect to have default behavior for permissions. In VerifyPermissionForXYZ define a new behavior you expect to have.VerifyPermissionForXYZ from your newly created test fixture.EXAMPLE: PermissionRequestWithPortalTest enables the Portals. The [PortalActivation] test verifies that permissions are disabled in Portals. VerifyPermissionsDeniedForPortal incapsulates all logic needed for a particular permission verification.