Add recommended extension installation support

extensions/browser/management_policy.h

 // Copyright 2013 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 EXTENSIONS_BROWSER_MANAGEMENT_POLICY_H_
 #define EXTENSIONS_BROWSER_MANAGEMENT_POLICY_H_
 
 #include <set>
 #include <string>
 
@@ skipping 56 matching lines @@
     // above, if they wish to completely lock in an extension.
     virtual bool MustRemainEnabled(const Extension* extension,
                                    base::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,
                                     base::string16* error) const;
 
+    // Similar to MustRemainEnabled, but for whether an extension must remain
+    // installed, and returns an error and/or reason if the caller needs it.
+    virtual bool MustRemainInstalled(const Extension* extension,
+                                     base::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.
@@ skipping 15 matching lines @@
   // message.
   bool MustRemainEnabled(const Extension* extension,
                          base::string16* error) const;
 
   // Returns true immediately if any registered provider's MustRemainDisabled
   // function returns true.
   bool MustRemainDisabled(const Extension* extension,
                           Extension::DisableReason* reason,
                           base::string16* error) const;
 
+  // Returns true immediately if any registered provider's MustRemainInstalled
+  // function returns true.
+  bool MustRemainInstalled(const Extension* extension,
+                           base::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*,
                                              base::string16*) const;
 
@@ skipping 11 matching lines @@
                            base::string16* error) const;
 
   ProviderList providers_;
 
   DISALLOW_COPY_AND_ASSIGN(ManagementPolicy);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_MANAGEMENT_POLICY_H_