Fix DCHECK() failures in XCursorLoader.

With the XCursorLoader changes in https://crrev.com/789288, comparisons
for |render_version_| do not work if |render_version_| is never set.
Make sure |render_version_| is valid before comparing it.

Bug: 1066670
Change-Id: I10c3c43d9b42403747fd073aa065ab3e8d00ed0a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2310961Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790828}

ui/base/x/x11_cursor_loader.cc

@@ -444,12 +444,12 @@ uint16_t XCursorLoader::CursorNamesToChar(
 
 bool XCursorLoader::SupportsCreateCursor() const {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  return render_version_ >= base::Version("0.5");
+  return render_version_.IsValid() && render_version_ >= base::Version("0.5");
 }
 
 bool XCursorLoader::SupportsCreateAnimCursor() const {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  return render_version_ >= base::Version("0.8");
+  return render_version_.IsValid() && render_version_ >= base::Version("0.8");
 }
 
 // This is ported from libxcb-cursor's parse_cursor_file.c: