Don't crash if WebAXObject::characterOffsets doesn't return any bounds.

components/test_runner/web_ax_object_proxy.cc

Index: components/test_runner/web_ax_object_proxy.cc
diff --git a/components/test_runner/web_ax_object_proxy.cc b/components/test_runner/web_ax_object_proxy.cc
index 1dbe3be923ceee7f453af8c15f00bab4d6773206..15f789487c7d6b13b80823db2f37541102071a13 100644
--- a/components/test_runner/web_ax_object_proxy.cc
+++ b/components/test_runner/web_ax_object_proxy.cc
@@ -357,8 +357,9 @@ blink::WebRect BoundsForCharacter(const blink::WebAXObject& object,
     int localIndex = characterIndex - start;
     blink::WebVector<int> character_offsets;
     inline_text_box.characterOffsets(character_offsets);
-    DCHECK(character_offsets.size() > 0 &&
-           character_offsets.size() == name.length());
+    if (character_offsets.size() != name.length())
+      return blink::WebRect();
+
     switch (inline_text_box.textDirection()) {
       case blink::WebAXTextDirectionLR: {
         if (localIndex) {