Limit PassiveDocumentEventListeners to touch and make it experimental

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 6d229ff00300898cbfd376a7aa9b005a32ce8d3e..33a2bf046aae1b0cdfdeb15b662a7b6d8773b0d2 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -5659,8 +5659,8 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_FLAGS_GESTURE_REQUIREMENT_FOR_MEDIA_PLAYBACK_DESCRIPTION" desc="Description for the flag for gesture requiment for media playback">
         User gesture requirement for playing media elements. Disabling this will allow autoplay to work.
       </message>
-      <message name="IDS_FLAGS_PASSIVE_DOCUMENT_EVENT_LISTENERS_DESCRIPTION" desc="Description for the flag to adjust the default behaviour for document level passive listeners.">
-        Forces touchstart, touchmove, mousewheel and wheel event listeners on document level targets (which haven't requested otherwise) to be treated as passive.
+      <message name="IDS_FLAGS_PASSIVE_DOCUMENT_EVENT_LISTENERS_DESCRIPTION" desc="Description for the flag to adjust the default behaviour for document level passive touch listeners.">
+        Forces touchstart, and touchmove event listeners on document level targets (which haven't requested otherwise) to be treated as passive.
       </message>
       <message name="IDS_FLAGS_PASSIVE_DOCUMENT_EVENT_LISTENERS_NAME" desc="Name for the flag to adjust the default behaviour for document level passive listeners.">
         Document Level Event Listeners Passive Default