Fixed ChromeOS clang build.

chrome/browser/automation/testing_automation_provider_chromeos.cc

Index: chrome/browser/automation/testing_automation_provider_chromeos.cc
diff --git a/chrome/browser/automation/testing_automation_provider_chromeos.cc b/chrome/browser/automation/testing_automation_provider_chromeos.cc
index 689b723b7331ec9b807fadd9b2a501d6ba71d2bc..2ffc792d9fff958819ad212c7237923d57e172fd 100644
--- a/chrome/browser/automation/testing_automation_provider_chromeos.cc
+++ b/chrome/browser/automation/testing_automation_provider_chromeos.cc
@@ -1128,3 +1128,11 @@ void TestingAutomationProvider::PowerChanged(
     const chromeos::PowerSupplyStatus& status) {
   power_status = status;
 }
+
+void TestingAutomationProvider::LockScreen() {
+  // Not used, but defined to make clang happy with the overloaded name.
+}
+
+void TestingAutomationProvider::UnlockScreen() {
+  // Not used, but defined to make clang happy with the overloaded name.
+}