Implement per-test timeout for UI tests.

chrome/test/automation/automation_proxy.cc

Index: chrome/test/automation/automation_proxy.cc
diff --git a/chrome/test/automation/automation_proxy.cc b/chrome/test/automation/automation_proxy.cc
index a039ffb33aeea187808522ae6a49900921ffeb2f..d2cfad7292334a1fc090e81ac4e1c8d200b00fc8 100644
--- a/chrome/test/automation/automation_proxy.cc
+++ b/chrome/test/automation/automation_proxy.cc
@@ -194,6 +194,10 @@ bool AutomationProxy::WaitForInitialLoads() {
   return initial_loads_complete_.TimedWait(command_execution_timeout_);
 }
 
+bool AutomationProxy::QuitAfterTimeout(int timeout_ms) {
+  return Send(new AutomationMsg_QuitAfterTimeout(0, timeout_ms));
+}
+
 bool AutomationProxy::WaitForInitialNewTabUILoad(int* load_time) {
   if (new_tab_ui_load_complete_.TimedWait(command_execution_timeout_)) {
     *load_time = new_tab_ui_load_time_;