If an element has unicode-bidi: plaintext and no strong directional characters. By default it should be LTR.

BUG=277687

Review URL: https://chromiumcodereview.appspot.com/23112019

git-svn-id: svn://svn.chromium.org/blink/trunk@156664 bbb929c8-8fbe-4397-9dbb-9b2b20218538
diff --git a/Source/core/css/html.css b/Source/core/css/html.css
index dff2fce..1fe1b6d 100644
--- a/Source/core/css/html.css
+++ b/Source/core/css/html.css
@@ -1112,6 +1112,10 @@
     unicode-bidi: bidi-override;
 }
 
+textarea[dir=auto] {
+    unicode-bidi: -webkit-plaintext;
+}
+
 /* page */
 
 @page {