BookmarkNodeData: Remove unnecessary TODO.

Turns out that ReadFromClipboard does use the buffer argument.

Here's[1] an overload supporting it, and here's[2] a use-case with kDrag.

[1]: https://cs.chromium.org/chromium/src/components/bookmarks/browser/bookmark_node_data_mac.mm?rcl=d5f58793b0d31cc3e2f05c23ba3194c4d5191da3&l=42
[2]: https://cs.chromium.org/chromium/src/chrome/browser/ui/cocoa/tab_contents/web_drag_bookmark_handler_mac.mm?rcl=d5f58793b0d31cc3e2f05c23ba3194c4d5191da3&l=27

Change-Id: I59c2645c865ed52215afaa4c111dcfbca4c26819
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1763213Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Darwin Huang <huangdarwin@chromium.org>
Auto-Submit: Darwin Huang <huangdarwin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689154}

components/bookmarks/browser/bookmark_node_data.h

@@ -131,7 +131,6 @@ struct BookmarkNodeData {
 
   // Reads bookmarks from the specified clipboard. Prefers data written via
   // WriteToClipboard() but will also attempt to read a plain bookmark.
-  // TODO(huangdarwin): Remove |buffer|, which only uses 1 enum value.
   bool ReadFromClipboard(ui::ClipboardBuffer buffer);
 
 #if defined(TOOLKIT_VIEWS)