commit 0088cd120e9b1edfc64f7c2732f64341db6a692d
author Dominic Mazzoni <dmazzoni@chromium.org> Wed Jul 11 20:40:08 2018
committer Commit Bot <commit-bot@chromium.org> Wed Jul 11 20:40:08 2018
tree 91423e9904ddbd3133f2b7ed39f4a1e99f6d87b5
parent cec0800c372ef670f59999fb3f028013d36b866c

Create concrete base class for AXPlatformNodeDelegate

The reason to make a pure-virtual class is to ensure that if someone
adds a new function it must be overridden by all subclasses.

Here are the subclasses of AXPlatformNodeDelegate, and how much they
implement / override:

* BrowserAccessibility: all
* NativeViewAccessibilityBase: most
* TestAXNodeWrapper: most
* AXSystemCaretWin: a little bit
* AuraLinuxApplication: a little bit

Every time we added a new interface, it didn't seem to make sense to
keep implementing them in AXSystemCaretWin and AuraLinuxApplication if
they weren't needed.

This change adds AXPlatformNodeDelegateBase with default
implementations of everything. Then most subclasses can
override exactly what they need and no more.

Bug: none
Change-Id: I7ad78e9403c92b576881969e035d14174222bb3d
Reviewed-on: https://chromium-review.googlesource.com/1132093
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574315}