Use devtools to set user agent in chromedriver

chrome/test/chromedriver/capabilities_unittest.cc

Index: chrome/test/chromedriver/capabilities_unittest.cc
diff --git a/chrome/test/chromedriver/capabilities_unittest.cc b/chrome/test/chromedriver/capabilities_unittest.cc
index a1a3e7ff248f9aa6e8ffa9783bb0d0421b830912..2887616924eee1a4f19ae955b7887318df2edc24 100644
--- a/chrome/test/chromedriver/capabilities_unittest.cc
+++ b/chrome/test/chromedriver/capabilities_unittest.cc
@@ -477,9 +477,7 @@ TEST(ParseCapabilities, MobileEmulationUserAgent) {
   Status status = capabilities.Parse(caps);
   ASSERT_TRUE(status.IsOk());
 
-  ASSERT_EQ(1u, capabilities.switches.GetSize());
-  ASSERT_TRUE(capabilities.switches.HasSwitch("user-agent"));
-  ASSERT_EQ("Agent Smith", capabilities.switches.GetSwitchValue("user-agent"));
+  ASSERT_EQ("Agent Smith", capabilities.user_agent);
 }
 
 TEST(ParseCapabilities, MobileEmulationDeviceMetrics) {
@@ -507,13 +505,11 @@ TEST(ParseCapabilities, MobileEmulationDeviceName) {
   Status status = capabilities.Parse(caps);
   ASSERT_TRUE(status.IsOk());
 
-  ASSERT_EQ(1u, capabilities.switches.GetSize());
-  ASSERT_TRUE(capabilities.switches.HasSwitch("user-agent"));
   ASSERT_EQ(
       "Mozilla/5.0 (Linux; Android 4.4.4; Nexus 5 Build/KTU84P) "
       "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.114 Mobile "
       "Safari/537.36",
-      capabilities.switches.GetSwitchValue("user-agent"));
+      capabilities.user_agent);
 
   ASSERT_EQ(360, capabilities.device_metrics->width);
   ASSERT_EQ(640, capabilities.device_metrics->height);