Move SelectionTemplate::is_handle_visible_ to FrameSelection

This patch moves |is_handle_visible_| to |FrameSelection| from |SelectionTemplate|
since handle visibility is used only for setting |FrameSelection|, hence it is
a redundant member variable of |SelectionTemplate|.

Bug: 742093
Change-Id: I3add4da3844fb40be34dcb4d4b46b5fa6fed1d7e
Reviewed-on: https://chromium-review.googlesource.com/595389
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Reviewed-by: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491660}
void GranularityStrategyTest::SetupVerticalAlign(String str1,
                                                 String str2,
                                                 String str3,
                                                 size_t sel_begin,
                                                 size_t sel_end) {
  SetInnerHTML(
      "<html>"
      "<head>"
      "<style>"
      "span {"
      "vertical-align:20px;"
      "}"
      "</style>"
      "</head>"
      "<body>"
      "<div id='mytext'></div>"
      "</body>"
      "</html>");

  SetupTextSpan(str1, str2, str3, sel_begin, sel_end);
}

void GranularityStrategyTest::SetupVerticalAlign(String str1,
                                                 String str2,
                                                 String str3,
                                                 size_t sel_begin,
                                                 size_t sel_end) {
  SetInnerHTML(
      "<html>"
      "<head>"
      "<style>"
      "span {"
      "vertical-align:20px;"
      "}"
      "</style>"
      "</head>"
      "<body>"
      "<div id='mytext'></div>"
      "</body>"
      "</html>");

  SetupTextSpan(str1, str2, str3, sel_begin, sel_end);
}
