Move some dependencies of ExtensionService down to extensions.

chrome/browser/extensions/management_policy.h

-// Copyright (c) 2012 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_EXTENSIONS_MANAGEMENT_POLICY_H_
-#define CHROME_BROWSER_EXTENSIONS_MANAGEMENT_POLICY_H_
-
-#include <set>
-#include <string>
-
-#include "base/basictypes.h"
-#include "extensions/common/extension.h"
-
-namespace extensions {
-
-// This class registers providers that want to prohibit certain actions from
-// being applied to extensions. It must be called, via the ExtensionService,
-// before allowing a user or a user-level mechanism to perform the respective
-// action. (That is, installing or otherwise modifying an extension in order
-// to conform to enterprise administrator policy must be exempted from these
-// checks.)
-//
-// This "policy" and its providers should not be confused with administrator
-// policy, although admin policy is one of the sources ("Providers") of
-// restrictions registered with and exposed by the ManagementPolicy.
-class ManagementPolicy {
- public:
-  // Each mechanism that wishes to limit users' ability to control extensions,
-  // whether one individual extension or the whole system, should implement
-  // the methods of this Provider interface that it needs. In each case, if the
-  // provider does not need to control a certain action, that method does not
-  // need to be implemented.
-  //
-  // It is not guaranteed that a particular Provider's methods will be called
-  // each time a user tries to perform one of the controlled actions (the list
-  // of providers is short-circuited as soon as a decision is possible), so
-  // implementations of these methods must have no side effects.
-  //
-  // For all of the Provider methods below, if |error| is not NULL and the
-  // method imposes a restriction on the desired action, |error| may be set
-  // to an applicable error message, but this is not required.
-  class Provider {
-   public:
-    Provider() {}
-    virtual ~Provider() {}
-
-    // A human-readable name for this provider, for use in debug messages.
-    // Implementers should return an empty string in non-debug builds, to save
-    // executable size.
-    virtual std::string GetDebugPolicyProviderName() const = 0;
-
-    // Providers should return false if a user may not install the |extension|,
-    // or load or run it if it has already been installed.
-    virtual bool UserMayLoad(const Extension* extension,
-                             string16* error) const;
-
-    // Providers should return false if a user may not enable, disable, or
-    // uninstall the |extension|, or change its usage options (incognito
-    // permission, file access, etc.).
-    virtual bool UserMayModifySettings(const Extension* extension,
-                                       string16* error) const;
-
-    // Providers should return true if the |extension| must always remain
-    // enabled. This is distinct from UserMayModifySettings() in that the latter
-    // also prohibits enabling the extension if it is currently disabled.
-    // Providers implementing this method should also implement the others
-    // above, if they wish to completely lock in an extension.
-    virtual bool MustRemainEnabled(const Extension* extension,
-                                   string16* error) const;
-
-    // Similar to MustRemainEnabled, but for whether an extension must remain
-    // disabled, and returns an error and/or reason if the caller needs it.
-    virtual bool MustRemainDisabled(const Extension* extension,
-                                    Extension::DisableReason* reason,
-                                    string16* error) const;
-
-   private:
-    DISALLOW_COPY_AND_ASSIGN(Provider);
-  };
-
-  ManagementPolicy();
-  ~ManagementPolicy();
-
-  // Registers or unregisters a provider, causing it to be added to or removed
-  // from the list of providers queried. Ownership of the provider remains with
-  // the caller. Providers do not need to be unregistered on shutdown.
-  void RegisterProvider(Provider* provider);
-  void UnregisterProvider(Provider* provider);
-
-  // Returns true if the user is permitted to install, load, and run the given
-  // extension. If not, |error| may be set to an appropriate message.
-  bool UserMayLoad(const Extension* extension, string16* error) const;
-
-  // Returns true if the user is permitted to enable, disable, or uninstall the
-  // given extension, or change the extension's usage options (incognito mode,
-  // file access, etc.). If not, |error| may be set to an appropriate message.
-  bool UserMayModifySettings(const Extension* extension,
-                             string16* error) const;
-
-  // Returns true if the extension must remain enabled at all times (e.g. a
-  // compoment extension). In that case, |error| may be set to an appropriate
-  // message.
-  bool MustRemainEnabled(const Extension* extension,
-                         string16* error) const;
-
-  // Returns true immediately if any registered provider's MustRemainDisabled
-  // function returns true.
-  bool MustRemainDisabled(const Extension* extension,
-                          Extension::DisableReason* reason,
-                          string16* error) const;
-
-  // For use in testing.
-  void UnregisterAllProviders();
-  int GetNumProviders() const;
-
- private:
-  // This is a pointer to a function in the Provider interface, used in
-  // ApplyToProviderList.
-  typedef bool (Provider::*ProviderFunction)(const Extension*, string16*) const;
-
-  typedef std::set<Provider*> ProviderList;
-
-  // This is a helper to apply a method in the Provider interface to each of
-  // the Provider objects in |providers_|. The return value of this function
-  // will be |normal_result|, unless any of the Provider calls to |function|
-  // return !normal_result, in which case this function will then early-return
-  // !normal_result.
-  bool ApplyToProviderList(ProviderFunction function,
-                           const char* debug_operation_name,
-                           bool normal_result,
-                           const Extension* extension,
-                           string16* error) const;
-
-  ProviderList providers_;
-
-  DISALLOW_COPY_AND_ASSIGN(ManagementPolicy);
-};
-
-}  // namespace extensions
-
-#endif  // CHROME_BROWSER_EXTENSIONS_MANAGEMENT_POLICY_H_