Display content of the annotation when mouse hover.

testing/SUPPRESSIONS

 # Copyright 2016 The PDFium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 # List of tests to be skipped, one per line.
 # There are four space-separated columns per line
 # Each column (except column 0) can contain a comma-separated list of values.
 #
 # Column 0: test file name
 # Column 1: platform: *, win, mac, linux
@@ skipping 263 matching lines @@
 action_reset.pdf mac * *
 action_run_javascript.pdf mac * *
 action_submit_a_form.pdf mac * *
 all_trigger_alert.pdf * * *
 all_trigger_browsefordoc.pdf * * *
 all_trigger_mailmsg.pdf * * *
 all_trigger_newdoc.pdf * * *
 all_trigger_print.pdf * * *
 all_trigger_run_js_lunchurl.pdf mac * *
 all_trigger_run_js_maildoc.pdf mac * *
+annotation_highlight_author_content.pdf mac * *
+annotation_highlight_long_content.pdf mac * *
+annotation_highlight_no_author.pdf mac * *
 app_launchurl.pdf mac * *
 appstoredescription3.1_en_updated.pdf mac * *
 bookmark.pdf * * *
 bookmarkgetcolor.pdf mac * *
 bug_0_length_line.pdf mac * *
 bug_0_width_line.pdf mac * *
 bug_434.pdf * * noxfa
 bug_434.pdf win * xfa
 bug_white_space.pdf mac * *
 calcorderindex_test.pdf * * *
@@ skipping 194 matching lines @@
 # xfa_specific
 #
 Choose.pdf * * *
 data_binding.pdf * * *
 Date_FormCale.pdf * * *
 Sum.pdf * * *
 TimeField.pdf * * *
 Test_CheckBox.pdf * * *
 Test_DateField_locale_zh_HK.pdf * * *