Fix how JsChecker::GetBoolImpl enforces boolean result

chrome/browser/chromeos/login/test/js_checker.cc

Index: chrome/browser/chromeos/login/test/js_checker.cc
diff --git a/chrome/browser/chromeos/login/test/js_checker.cc b/chrome/browser/chromeos/login/test/js_checker.cc
index 0b5db2c7dde8e6c6d3e850c6eae7eb726b645044..6ccc5ab2a3a43b4da3d2ffa276bbc4c70a6fde1e 100644
--- a/chrome/browser/chromeos/login/test/js_checker.cc
+++ b/chrome/browser/chromeos/login/test/js_checker.cc
@@ -86,9 +86,8 @@ void JSChecker::ExpectNE(const std::string& expression,
 
 void JSChecker::GetBoolImpl(const std::string& expression, bool* result) {
   CHECK(web_contents_);
-  ASSERT_TRUE(content::ExecuteScriptAndExtractBool(web_contents_,
-                                                   "!!" + WrapSend(expression),
-                                                   result));
+  ASSERT_TRUE(content::ExecuteScriptAndExtractBool(
+      web_contents_, WrapSend("!!(" + expression + ")"), result));
 }
 
 void JSChecker::GetIntImpl(const std::string& expression, int* result) {