Move hyper-text from BrowserAccessibility to AXPlatformNode.

This CL moves the hyperlink/hypertext data from BrowserAccessibilityComWin
to AXPlatformNodeWin.  It also introduces GetText() on the AXPlatformNodeBase
which is used to access either the innerhtml or the hypertext.

Note that many of the BrowserAccessibilityComWin methods dealing with hyper
text will be moved over to AXPlatformNodeWin in a followup.

Bug: 703369
Change-Id: I05c85f9169492a5a754dbf6166056ef926226af9
Reviewed-on: https://chromium-review.googlesource.com/639320
Commit-Queue: Doug Turner <dougt@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#499630}
7 files changed