Do not post hint descriptors back to the frame itself.

When distributing hint descriptors, do not post a frame's own hint
descriptors back to the frame itself.  It already has them.

With regard to the message-passing cost only, this represents a speedup
of approximately 3/2 for link-busy sites like reddit -- several tens of
milliseconds for me.  There are other costs too (such as processing the
hint descriptors) bu these are not affected.

1 files changed, 6 insertions, 2 deletions

diff --git a/content_scripts/link_hints.coffee b/content_scripts/link_hints.coffee
index 56cea78d..70c51eac 100644
--- a/content_scripts/link_hints.coffee
+++ b/content_scripts/link_hints.coffee
@@ -82,13 +82,17 @@ HintCoordinator =
     DomUtils.documentReady => Settings.onLoaded =>
       requireHref = availableModes[modeIndex] in [COPY_LINK_URL, OPEN_INCOGNITO]
       @localHints = LocalHints.getLocalHints requireHref
-      @sendMessage "postHintDescriptors", hintDescriptors:
-        @localHints.map ({linkText}, localIndex) -> {frameId, localIndex, linkText}
+      @localHintDescriptors = @localHints.map ({linkText}, localIndex) -> {frameId, localIndex, linkText}
+      @sendMessage "postHintDescriptors", hintDescriptors: @localHintDescriptors
 
   # We activate LinkHintsMode() in every frame and provide every frame with exactly the same hint descriptors.
   # We also propagate the key state between frames.  Therefore, the hint-selection process proceeds in lock
   # step in every frame, and @linkHintsMode is in the same state in every frame.
   activateMode: ({hintDescriptors, modeIndex, originatingFrameId}) ->
+    # We do not receive the frame's own hint descritors back from the background page.  Instead, we merge them
+    # with the hint descriptors from other frames here.
+    [hintDescriptors[frameId], @localHintDescriptors] = [@localHintDescriptors, null]
+    hintDescriptors = [].concat (hintDescriptors[fId] for fId in (fId for own fId of hintDescriptors).sort())...
     # Ensure that the document is ready and that the settings are loaded.
     DomUtils.documentReady => Settings.onLoaded =>
       @suppressKeyboardEvents.exit() if @suppressKeyboardEvents?.modeIsActive