Bug 1034679 - Add isEnabledStateLocked property to visually disable plug-ins with locked states in Add-ons Manager. r=bsmedberg

dom/plugins/base/nsIPluginTag.idl

@@ -5,7 +5,7 @@
 
 #include "nsISupports.idl"
 
-[scriptable, uuid(0e56f04d-cda4-4a55-ab83-e5e29ddd370e)]
+[scriptable, uuid(231df043-3a32-43c4-aaac-7ad2da81e84f)]
 interface nsIPluginTag : nsISupports
 {
   // enabledState is stored as one of the following as an integer in prefs,
@@ -25,6 +25,11 @@ interface nsIPluginTag : nsISupports
    */
   readonly attribute boolean blocklisted;
 
+  /**
+   * true if the state is non-default and locked, false otherwise.
+   */
+  readonly attribute boolean isEnabledStateLocked;
+
   readonly attribute boolean disabled;
   readonly attribute boolean clicktoplay;
            attribute unsigned long enabledState;

dom/plugins/base/nsPluginTags.cpp

@@ -16,6 +16,7 @@
 #include "nsPluginLogging.h"
 #include "nsNPAPIPlugin.h"
 #include "mozilla/Preferences.h"
+#include "mozilla/unused.h"
 #include <cctype>
 #include "mozilla/dom/EncodingUtils.h"
 
@@ -340,6 +341,22 @@ nsPluginTag::GetBlocklisted(bool* aBlocklisted)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsPluginTag::GetIsEnabledStateLocked(bool* aIsEnabledStateLocked)
+{
+  *aIsEnabledStateLocked = false;
+  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
+
+  if (NS_WARN_IF(!prefs)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  unused << prefs->PrefIsLocked(GetStatePrefNameForPlugin(this).get(),
+                                aIsEnabledStateLocked);
+
+  return NS_OK;
+}
+
 bool
 nsPluginTag::IsClicktoplay()
 {