Update ChromeDriver to accept W3C format InitSession

chrome/test/chromedriver/session_commands.cc

Index: chrome/test/chromedriver/session_commands.cc
diff --git a/chrome/test/chromedriver/session_commands.cc b/chrome/test/chromedriver/session_commands.cc
index 1a39f53bc3a0574e07e8fb9e9ea019677c0ae3ee..3bcbd9a92aa400a7c1ce15ad990fdf0ea9e445c6 100644
--- a/chrome/test/chromedriver/session_commands.cc
+++ b/chrome/test/chromedriver/session_commands.cc
@@ -177,13 +177,21 @@ Status InitSessionHelper(const InitSessionParams& bound_params,
       new WebDriverLog(WebDriverLog::kDriverType, Log::kAll));
   const base::DictionaryValue* desired_caps;
   bool w3c_capability = false;
-  if (params.GetDictionary("capabilities.desiredCapabilities", &desired_caps)
+  if (params.GetDictionary("capabilities.alwaysMatch", &desired_caps)
       && desired_caps->GetBoolean("chromeOptions.w3c", &w3c_capability)
-      && w3c_capability)
+      && w3c_capability) {
+    // TODO(johnchen): Handle capabilities.firstMatch.
     session->w3c_compliant = true;
-  else if (!params.GetDictionary("desiredCapabilities", &desired_caps) &&
-     !params.GetDictionary("capabilities.desiredCapabilities", &desired_caps))
-    return Status(kUnknownError, "cannot find dict 'desiredCapabilities'");
+  } else if (params.GetDictionary("capabilities.desiredCapabilities",
+                                  &desired_caps)
+             && desired_caps->GetBoolean("chromeOptions.w3c", &w3c_capability)
+             && w3c_capability) {
+    // TODO(johnchen): Remove when clients stop using this.
+    session->w3c_compliant = true;
+  } else if (!params.GetDictionary("desiredCapabilities", &desired_caps)) {
+    return Status(kSessionNotCreatedException,
+                  "Missing or invalid capabilities");
+  }
 
   Capabilities capabilities;
   Status status = capabilities.Parse(*desired_caps);