Don't fire Alt-Search binding when Alt-Search is being used for accessing a modifer key.

ash/accelerators/accelerator_controller.cc

Index: ash/accelerators/accelerator_controller.cc
diff --git a/ash/accelerators/accelerator_controller.cc b/ash/accelerators/accelerator_controller.cc
index fbe39d16a2bef57acd9b520adb457ee134d8c662..656dbc7e7cc926df1f0a42ffc3bb38ad3ca97649 100644
--- a/ash/accelerators/accelerator_controller.cc
+++ b/ash/accelerators/accelerator_controller.cc
@@ -583,6 +583,15 @@ bool AcceleratorController::PerformAction(int action,
       }
       return false;
     case TOGGLE_CAPS_LOCK:
+      if (key_code == ui::VKEY_LWIN) {
+        // If something else was pressed between the Search key (LWIN)
+        // being pressed and released, then ignore the release of the
+        // Search key.
+        // TODO(danakj): Releasing Alt first breaks this: crbug.com/166495
+        if (previous_event_type == ui::ET_KEY_RELEASED ||
+            previous_key_code != ui::VKEY_LWIN)
+          return false;
+      }
       shell->caps_lock_delegate()->ToggleCapsLock();
       return true;
     case BRIGHTNESS_DOWN: