Enable Child/Geller to remove BLOCKED or REQUIRE_APPROVAL extensions

Child/Geller users currently cannot remove extensions with state
BLOCKED or REQUIRE_APPROVAL because UserMayModifySettings() returns
false. Make UserMayModifySettings() always return true so that child/
Geller users can remove installed extensions regardless of the state.

Bug: 1033687,1032352
Change-Id: I4608c22099325578982e48b6da31840c124167d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1969068
Commit-Queue: Toby Huang <tobyhuang@chromium.org>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#728660}

chrome/browser/supervised_user/supervised_user_service.cc

@@ -779,18 +779,6 @@ bool SupervisedUserService::UserMayLoad(const Extension* extension,
   return may_load;
 }
 
-bool SupervisedUserService::UserMayModifySettings(const Extension* extension,
-                                                  base::string16* error) const {
-  DCHECK(ProfileIsSupervised());
-  ExtensionState result = GetExtensionState(*extension);
-  // Only allow the supervised user to modify the settings and enable or disable
-  // the extension if the supervised user has full control.
-  bool may_modify = result == ExtensionState::ALLOWED;
-  if (!may_modify && error)
-    *error = GetExtensionsLockedMessage();
-  return may_modify;
-}
-
 bool SupervisedUserService::MustRemainDisabled(
     const Extension* extension,
     extensions::disable_reason::DisableReason* reason,

chrome/browser/supervised_user/supervised_user_service.h

@@ -215,8 +215,6 @@ class SupervisedUserService : public KeyedService,
   std::string GetDebugPolicyProviderName() const override;
   bool UserMayLoad(const extensions::Extension* extension,
                    base::string16* error) const override;
-  bool UserMayModifySettings(const extensions::Extension* extension,
-                             base::string16* error) const override;
   bool MustRemainDisabled(const extensions::Extension* extension,
                           extensions::disable_reason::DisableReason* reason,
                           base::string16* error) const override;

chrome/browser/supervised_user/supervised_user_service_unittest.cc

@@ -531,9 +531,9 @@ TEST_F(SupervisedUserServiceExtensionTest,
     EXPECT_FALSE(error_3.empty());
 
     base::string16 error_4;
-    EXPECT_FALSE(supervised_user_service->UserMayModifySettings(extension.get(),
-                                                                &error_4));
-    EXPECT_FALSE(error_4.empty());
+    EXPECT_TRUE(supervised_user_service->UserMayModifySettings(extension.get(),
+                                                               &error_4));
+    EXPECT_TRUE(error_4.empty());
 
     base::string16 error_5;
     EXPECT_TRUE(