Refactor the various ways to control what users can do to extensions.

chrome/browser/extensions/extension_prefs.cc

Index: chrome/browser/extensions/extension_prefs.cc
===================================================================
--- chrome/browser/extensions/extension_prefs.cc	(revision 138227)
+++ chrome/browser/extensions/extension_prefs.cc	(working copy)
@@ -21,6 +21,8 @@
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/notification_service.h"
+#include "grit/generated_resources.h"
+#include "ui/base/l10n/l10n_util.h"
 
 using extensions::Extension;
 using extensions::ExtensionInfo;
@@ -659,15 +661,17 @@
                       Value::CreateBooleanValue(value));
 }
 
-bool ExtensionPrefs::IsExtensionAllowedByPolicy(
-    const std::string& extension_id,
-    Extension::Location location) const {
-  base::StringValue id_value(extension_id);
+std::string ExtensionPrefs::PolicyProviderName() const {

[Aaron Boodman, 2012/05/22 15:56:11]

Methods should typically be verb phrases, so GetPolicyProviderName().

+  return "admin policy black/whitelist, via the ExtensionPrefs";
+}
 
-  if (location == Extension::COMPONENT ||
-      location == Extension::EXTERNAL_POLICY_DOWNLOAD) {
+bool ExtensionPrefs::UserMayLoad(const extensions::Extension* extension,
+                                 extensions::Extension::Location location,
+                                 string16* error) const {
+  base::StringValue id_value(extension->id());
+
+  if (extensions::Extension::IsRequired(location))

[Pam (message me for reviews), 2012/05/22 12:51:07]

It's a rename (and direction flip) of Extension::UserMayDisable(). It returns
true if an extension must remain installed and enabled, namely if it's a
component or external-policy extension.

[Aaron Boodman, 2012/05/22 15:56:11]

Ah. Can that bit be moved into extensions::ManagementPolicy? Is there a reason
for it to be accessible on its own?

[Pam (message me for reviews), 2012/05/23 15:00:58]

On 2012/05/22 15:56:11, Aaron Boodman wrote:
 Can that bit be moved into extensions::ManagementPolicy? Is there a reason
I don't want to pollute extensions::ManagementPolicy with direct knowledge of
any of the policies.

I assume the former UserMayDisable was in Extension because that's where the
Extension::Location and a bunch of other methods with implementations that only
depend on the location (IsAutoUpdateableLocation, ShouldAlwaysAllowFileAccess,
etc.) are. I can't think of a better place for it, but am open to suggestions.

[Aaron Boodman, 2012/05/24 08:11:23]

OK, I see.

     return true;
-  }
 
   const base::ListValue* blacklist =
       prefs_->GetList(prefs::kExtensionInstallDenyList);
@@ -681,8 +685,15 @@
     return true;
 
   // Then check the blacklist (the admin blacklist, not the Google blacklist).
-  return blacklist->Find(id_value) == blacklist->end() &&
-         !ExtensionsBlacklistedByDefault();
+  bool result = blacklist->Find(id_value) == blacklist->end() &&
+      !ExtensionsBlacklistedByDefault();
+  if (error && !result) {
+    *error = l10n_util::GetStringFUTF16(
+          IDS_EXTENSION_CANT_INSTALL_POLICY_BLACKLIST,
+          UTF8ToUTF16(extension->name()),
+          UTF8ToUTF16(extension->id()));
+  }
+  return result;
 }
 
 bool ExtensionPrefs::ExtensionsBlacklistedByDefault() const {