[chromedriver] Check document.hasFocus() for IsElementFocus

document.activeElement could return body when no element has
focus. When user first navigate to url or switch frame, we
don't want to treat this body as focus. Therefore, we will
check document.hasFocus() first.

Bug: chromedriver:3502,b/157759309
Change-Id: I87e649423a6fde55a7b8a273c3500787045edac3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2225521Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Shengfa Lin <shengfa@google.com>
Cr-Commit-Position: refs/heads/master@{#774266}

chrome/test/chromedriver/element_util.cc

@@ -422,13 +422,30 @@ Status GetActiveElement(Session* session,
   return status;
 }
 
+Status HasFocus(Session* session, WebView* web_view, bool* hasFocus) {
+  std::unique_ptr<base::Value> value;
+  Status status = web_view->EvaluateScript(
+      session->GetCurrentFrameId(), "document.hasFocus()", false, &value);
+  if (status.IsError())
+    return status;
+  if (!value->is_bool())
+    return Status(kUnknownError, "document.hasFocus() returns non-boolean");
+  *hasFocus = value->GetBool();
+  return Status(kOk);
+}
+
 Status IsElementFocused(
     Session* session,
     WebView* web_view,
     const std::string& element_id,
     bool* is_focused) {
   std::unique_ptr<base::Value> result;
-  Status status = GetActiveElement(session, web_view, &result);
+  Status status = HasFocus(session, web_view, is_focused);
+  if (status.IsError())
+    return status;
+  if (!(*is_focused))
+    return status;
+  status = GetActiveElement(session, web_view, &result);
   if (status.IsError())
     return status;
   std::unique_ptr<base::Value> element_dict(CreateElement(element_id));