Fix scroll behavior when node has tab chars (facebookarchive#2256)

Summary:
Closes facebookarchive#2254

Problem behavior and reasoning behind solution is described in the issue.

The linter issues are unrelated to the file I changed so I left them alone in order to keep this commit atomic.
Pull Request resolved: facebookarchive#2256

Reviewed By: claudiopro

Differential Revision: D18734244

Pulled By: mrkev

fbshipit-source-id: eb5a1a91f7c3f27fced1e37f5822bc3e126fb332

src/component/handlers/edit/editOnBeforeInput.js

@@ -155,29 +155,6 @@ function editOnBeforeInput(
       editor._latestCommittedEditorState,
     );
   }
-  if (!mustPreventNative) {
-    // Chrome will also split up a node into two pieces if it contains a Tab
-    // char, for no explicable reason. Seemingly caused by this commit:
-    // https://chromium.googlesource.com/chromium/src/+/013ac5eaf3%5E%21/
-
-    // in test environment, e.target is not available
-    const nativeSelection = (e.currentTarget
-      ? e.currentTarget.ownerDocument.defaultView
-      : global
-    ).getSelection();
-    // Selection is necessarily collapsed at this point due to earlier check.
-    if (
-      nativeSelection.anchorNode &&
-      nativeSelection.anchorNode.nodeType === Node.TEXT_NODE
-    ) {
-      // See isTabHTMLSpanElement in chromium EditingUtilities.cpp.
-      const parentNode = nativeSelection.anchorNode.parentNode;
-      mustPreventNative =
-        parentNode.nodeName === 'SPAN' &&
-        parentNode.firstChild.nodeType === Node.TEXT_NODE &&
-        parentNode.firstChild.nodeValue.indexOf('\t') !== -1;
-    }
-  }
   if (!mustPreventNative) {
     // Let's say we have a decorator that highlights hashtags. In many cases
     // we need to prevent native behavior and rerender ourselves --