Tidy up permission_context_base.h

This CL fixes some comments in permission_context_base.h which are
outdated or incorrect, and moves PermissionDecided from protected to
private.

Change-Id: I62ed3d82f46dc8680656c6072d9e45f4585197dd
Reviewed-on: https://chromium-review.googlesource.com/776493Reviewed-by: Raymes Khoury <raymes@chromium.org>
Commit-Queue: Timothy Loh <timloh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517757}

chrome/browser/permissions/permission_context_base.h

@@ -42,8 +42,6 @@ using BrowserPermissionCallback = base::Callback<void(ContentSetting)>;
 //   - Define your new permission in the ContentSettingsType enum.
 //   - Create a class that inherits from PermissionContextBase and passes the
 //     new permission.
-//   - Inherit from PermissionInfobarDelegate and implement
-//     |GetMessageText|
 //   - Edit the PermissionRequestImpl methods to add the new text.
 //   - Hit several asserts for the missing plumbing and fix them :)
 // After this you can override several other methods to customize behavior,
@@ -70,9 +68,8 @@ class PermissionContextBase : public KeyedService {
   // PermissionContextBase can use it.
   static const char kPermissionsKillSwitchBlockedValue[];
 
-  // The renderer is requesting permission to push messages.
-  // When the answer to a permission request has been determined, |callback|
-  // should be called with the result.
+  // |callback| is called upon resolution of the request, but not if a prompt
+  // is shown and ignored.
   virtual void RequestPermission(content::WebContents* web_contents,
                                  const PermissionRequestID& id,
                                  const GURL& requesting_frame,
@@ -117,9 +114,8 @@ class PermissionContextBase : public KeyedService {
       const GURL& requesting_origin,
       const GURL& embedding_origin) const;
 
-  // Decide whether the permission should be granted.
-  // Calls PermissionDecided if permission can be decided non-interactively,
-  // or NotifyPermissionSet if permission decided by presenting an infobar.
+  // Called if generic checks (existing content setting, embargo, etc.) fail to
+  // resolve a permission request. The default implementation prompts the user.
   virtual void DecidePermission(content::WebContents* web_contents,
                                 const PermissionRequestID& id,
                                 const GURL& requesting_origin,
@@ -127,15 +123,8 @@ class PermissionContextBase : public KeyedService {
                                 bool user_gesture,
                                 const BrowserPermissionCallback& callback);
 
-  // Called when permission is granted without interactively asking the user.
-  void PermissionDecided(const PermissionRequestID& id,
-                         const GURL& requesting_origin,
-                         const GURL& embedding_origin,
-                         bool user_gesture,
-                         const BrowserPermissionCallback& callback,
-                         bool persist,
-                         ContentSetting content_setting);
-
+  // Updates stored content setting if persist is set, updates tab indicators
+  // and runs the callback to finish the request.
   virtual void NotifyPermissionSet(const PermissionRequestID& id,
                                    const GURL& requesting_origin,
                                    const GURL& embedding_origin,
@@ -185,6 +174,16 @@ class PermissionContextBase : public KeyedService {
                                  const BrowserPermissionCallback& callback,
                                  bool permission_blocked);
 
+  // This is the callback for PermissionRequestImpl and is called once the user
+  // allows/blocks/dismisses a permission prompt.
+  void PermissionDecided(const PermissionRequestID& id,
+                         const GURL& requesting_origin,
+                         const GURL& embedding_origin,
+                         bool user_gesture,
+                         const BrowserPermissionCallback& callback,
+                         bool persist,
+                         ContentSetting content_setting);
+
   // Called when the user has made a permission decision. This is a hook for
   // descendent classes to do appropriate things they might need to do when this
   // happens.