Introduce lock screen app context to extension features

extensions/renderer/script_context_set.h

Index: extensions/renderer/script_context_set.h
diff --git a/extensions/renderer/script_context_set.h b/extensions/renderer/script_context_set.h
index eddefb7c67a2ef0cc75d7c834a7a7a1c0a40b558..db90129e94d68a4b4b4c5222d9dfce0ca9d1c970 100644
--- a/extensions/renderer/script_context_set.h
+++ b/extensions/renderer/script_context_set.h
@@ -40,7 +40,7 @@ class ScriptContext;
 // changing underneath callers.
 class ScriptContextSet {
  public:
-  ScriptContextSet(
+  explicit ScriptContextSet(
       // Set of the IDs of extensions that are active in this process.
       // Must outlive this. TODO(kalman): Combine this and |extensions|.
       ExtensionIdSet* active_extension_ids);
@@ -106,6 +106,10 @@ class ScriptContextSet {
   // Cleans up contexts belonging to an unloaded extension.
   void OnExtensionUnloaded(const std::string& extension_id);
 
+  void set_lock_screen_context(bool lock_screen_context) {

[Devlin, 2017/06/01 22:17:58]

nit: prefer set_*is*_lock_screen_context (to differentiate between a bool and,
e.g., a browser context)

[tbarzic, 2017/06/02 00:49:05]

Done.

+    lock_screen_context_ = lock_screen_context;
+  }
+
   // Adds the given |context| for testing purposes.
   void AddForTesting(std::unique_ptr<ScriptContext> context);
 
@@ -133,6 +137,10 @@ class ScriptContextSet {
   // The set of all ScriptContexts we own.
   std::set<ScriptContext*> contexts_;
 
+  // Whether the script context set is associated with the renderer active on
+  // the Chrome OS lock screen.
+  bool lock_screen_context_ = false;
+
   DISALLOW_COPY_AND_ASSIGN(ScriptContextSet);
 };