Fix todo's in AXPlatformNodeWin::get_accRole related to string results.

For historical reasons, AXPlatformNodeWin::get_accRole can return a string
which can containing the HTML tag name as the MSAA role, rather than a int.

In some cases, we special cased roles such that they alway returned a specific
string instead of the underlying HTML tag name. For example, AX_ROLE_PARAGRAPH
always returned upper case "P".

What this CL does is removes some of these special cases in favor of just
returning the uppercase of the HTML tag name.

This is a follow up from issue 2909853002.

BUG=703369

Review-Url: https://codereview.chromium.org/2912243002
Cr-Commit-Position: refs/heads/master@{#477216}
9 files changed