Cleanup: remove use_existing_browser infrastructure from ui_test.

chrome/app/chrome_main_uitest.cc

Index: chrome/app/chrome_main_uitest.cc
diff --git a/chrome/app/chrome_main_uitest.cc b/chrome/app/chrome_main_uitest.cc
index 3ea43438e518f1e30608ed2ddaf395e1adfd8bc5..8d13b895dda09e4e9ef2ba796ff63af8e3d66bca 100644
--- a/chrome/app/chrome_main_uitest.cc
+++ b/chrome/app/chrome_main_uitest.cc
@@ -46,7 +46,6 @@ TEST_F(ChromeMainTest, AppTestingInterface) {
 // Make sure that the second invocation creates a new window.
 TEST_F(ChromeMainTest, SecondLaunch) {
   include_testing_id_ = false;
-  use_existing_browser_ = true;
 
   ASSERT_TRUE(LaunchAnotherBrowserBlockUntilClosed(
                   CommandLine(CommandLine::ARGUMENTS_ONLY)));
@@ -61,7 +60,6 @@ TEST_F(ChromeMainTest, SecondLaunch) {
 #endif
 TEST_F(ChromeMainTest, ReuseBrowserInstanceWhenOpeningFile) {
   include_testing_id_ = false;
-  use_existing_browser_ = true;
 
   FilePath test_file = test_data_directory_.AppendASCII("empty.html");