Add a fuzzer for BrowserAccessibility code.

I think it'd be good to have a fuzzer that creates some
random accessibility trees with lots of random ignored
nodes, to test functions like PlatformDeepestLastChild that
are crashing for an unknown reason.

Perhaps we can also use this as a template to create some
platform-specific fuzzers for public accessibility APIs.

Bug: 989997

Change-Id: I9e62f174c7722e4add1dbf7ead510fd37b394e7c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1780944
Reviewed-by: Max Moroz <[email protected]>
Reviewed-by: Aaron Leventhal <[email protected]>
Commit-Queue: Dominic Mazzoni <[email protected]>
Cr-Commit-Position: refs/heads/master@{#693000}
diff --git a/content/browser/BUILD.gn b/content/browser/BUILD.gn
index 8102b7e..25617596 100644
--- a/content/browser/BUILD.gn
+++ b/content/browser/BUILD.gn
@@ -27,6 +27,7 @@
     "//content/app:*",
     "//content/public/browser:browser_sources",
     "//content/test/fuzzer:appcache_fuzzer",
+    "//content/test/fuzzer:browser_accessibility_fuzzer",
   ]
 
   configs += [