Add more management policy checking after extension installed

This CL adds checking for MustRemainDisabled() from management policy after an extension is installed or updated, so that extensions supposed to be disabled will be disabled initially with proper disabled reason set.

This CL also assumes that all disabled extension comes with proper disabled reason, so there are additional changes to ensure this.

1) Another extension disabled reason DISABLE_EXTERNAL_EXTENSION is added for external extensions. These extensions will be disabled initially on windows for user prompting.
2) Two tests from extension_disabled_ui_browsertest.cc is removed since these two tests are meant for legacy disables with not disabled reason set in user pref, which should be rarely seen now. And these rare cases are handled by presuming it's disabled by user action as well.

BUG=None

Review URL: https://codereview.chromium.org/714133002

Cr-Commit-Position: refs/heads/master@{#304587}

1 files changed, 3 insertions, 1 deletions

diff --git a/extensions/common/extension.h b/extensions/common/extension.h
index 4c76478..391c7e5 100644
--- a/extensions/common/extension.h
+++ b/extensions/common/extension.h
@@ -102,7 +102,9 @@ class Extension : public base::RefCountedThreadSafe<Extension> {
     DISABLE_REMOTE_INSTALL = 1 << 11,
     DISABLE_INACTIVE_EPHEMERAL_APP = 1 << 12,  // Cached ephemeral apps are
                                                // disabled to prevent activity.
-    DISABLE_REASON_LAST = 1 << 13,  // This should always be the last value
+    DISABLE_EXTERNAL_EXTENSION = 1 << 13,  // External extensions might be
+                                           // disabled for user prompting.
+    DISABLE_REASON_LAST = 1 << 14,  // This should always be the last value
   };
 
   // A base class for parsed manifest data that APIs want to store on