Keep browser process alive while there are platform apps with background pages running.

chrome/browser/extensions/api/socket/socket_apitest.cc

Index: chrome/browser/extensions/api/socket/socket_apitest.cc
diff --git a/chrome/browser/extensions/api/socket/socket_apitest.cc b/chrome/browser/extensions/api/socket/socket_apitest.cc
index 93bd3c8c089b504c8619b810a7925189df0452c3..d27971722584f20b3ccf3f8db4850f5a40b29f22 100644
--- a/chrome/browser/extensions/api/socket/socket_apitest.cc
+++ b/chrome/browser/extensions/api/socket/socket_apitest.cc
@@ -145,6 +145,7 @@ IN_PROC_BROWSER_TEST_F(SocketApiTest, SocketUDPExtension) {
       base::StringPrintf("udp:%s:%d", host_port_pair.host().c_str(), port));
 
   EXPECT_TRUE(catcher.GetNextResult()) << catcher.message();
+  CloseShellWindowsAndWaitForAppToExit();
 }
 
 IN_PROC_BROWSER_TEST_F(SocketApiTest, SocketTCPExtension) {
@@ -172,6 +173,7 @@ IN_PROC_BROWSER_TEST_F(SocketApiTest, SocketTCPExtension) {
       base::StringPrintf("tcp:%s:%d", host_port_pair.host().c_str(), port));
 
   EXPECT_TRUE(catcher.GetNextResult()) << catcher.message();
+  CloseShellWindowsAndWaitForAppToExit();
 }
 
 IN_PROC_BROWSER_TEST_F(SocketApiTest, SocketTCPServerExtension) {
@@ -184,9 +186,12 @@ IN_PROC_BROWSER_TEST_F(SocketApiTest, SocketTCPServerExtension) {
       base::StringPrintf("tcp_server:%s:%d", kHostname.c_str(), kPort));
 
   EXPECT_TRUE(catcher.GetNextResult()) << catcher.message();
+  CloseShellWindowsAndWaitForAppToExit();
 }
 
 IN_PROC_BROWSER_TEST_F(SocketApiTest, SocketTCPServerUnbindOnUnload) {
   ASSERT_TRUE(RunExtensionTest("socket/unload")) << message_;
+  CloseShellWindowsAndWaitForAppToExit();
   ASSERT_TRUE(RunExtensionTest("socket/unload")) << message_;
+  CloseShellWindowsAndWaitForAppToExit();
 }