[chromedriver] Add a sanity check during session initiation

BUG=chromedriver:1058

Review URL: https://codereview.chromium.org/1004333002

Cr-Commit-Position: refs/heads/master@{#320661}

chrome/test/chromedriver/session_commands.cc

@@ -105,6 +105,32 @@ scoped_ptr<base::DictionaryValue> CreateCapabilities(Chrome* chrome) {
   return caps.Pass();
 }
 
+Status CheckSessionCreated(Session* session) {
+  WebView* web_view = NULL;
+  Status status = session->GetTargetWindow(&web_view);
+  if (status.IsError())
+    return Status(kSessionNotCreatedException, status);
+
+  status = web_view->ConnectIfNecessary();
+  if (status.IsError())
+    return Status(kSessionNotCreatedException, status);
+
+  base::ListValue args;
+  scoped_ptr<base::Value> result(new base::FundamentalValue(0));
+  status = web_view->CallFunction(session->GetCurrentFrameId(),
+                                  "function(s) { return 1; }", args, &result);
+  if (status.IsError())
+    return Status(kSessionNotCreatedException, status);
+
+  int response;
+  if (!result->GetAsInteger(&response) || response != 1) {
+    return Status(kSessionNotCreatedException,
+                  "unexpected response from browser");
+  }
+
+  return Status(kOk);
+}
+
 Status InitSessionHelper(
     const InitSessionParams& bound_params,
     Session* session,
@@ -165,7 +191,7 @@ Status InitSessionHelper(
   session->force_devtools_screenshot = capabilities.force_devtools_screenshot;
   session->capabilities = CreateCapabilities(session->chrome.get());
   value->reset(session->capabilities->DeepCopy());
-  return Status(kOk);
+  return CheckSessionCreated(session);
 }
 
 }  // namespace