Get rid of AX_LINE_BREAKS attribute to improve performance.

chrome/test/data/extensions/api_test/automation/tests/tabs/line_start_offsets.js

Index: chrome/test/data/extensions/api_test/automation/tests/tabs/line_start_offsets.js
diff --git a/chrome/test/data/extensions/api_test/automation/tests/tabs/line_start_offsets.js b/chrome/test/data/extensions/api_test/automation/tests/tabs/line_start_offsets.js
new file mode 100644
index 0000000000000000000000000000000000000000..ed2134ae694ae7527e02b6ef1faf41cd4a8974f3
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/automation/tests/tabs/line_start_offsets.js
@@ -0,0 +1,33 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var allTests = [
+  function testInput() {
+    var textFields = rootNode.findAll({ role: RoleType.textField });
+    assertEq(2, textFields.length);
+    var input = textFields[0];
+    assertTrue(!!input);
+    assertTrue('lineStartOffsets' in input);
+    var lineStarts = input.lineStartOffsets;
+    assertEq(1, lineStarts.length);
+    assertEq(9, lineStarts[0]);
+    chrome.test.succeed();
+  },
+
+  function testTextarea() {
+    var textFields = rootNode.findAll({ role: RoleType.textField });
+    assertEq(2, textFields.length);
+    var textarea = textFields[1];
+    assertTrue(!!textarea);
+    assertTrue('lineStartOffsets' in textarea);
+    var lineStarts = textarea.lineStartOffsets;
+    assertEq(3, lineStarts.length);
+    assertEq(10, lineStarts[0]);
+    assertEq(20, lineStarts[1]);
+    assertEq(31, lineStarts[2]);
+    chrome.test.succeed();
+  }
+];
+
+setUpAndRunTests(allTests, 'line_start_offsets.html');