Make GlobalDescriptors::MaybeGet return -1 when the key is not found.

ipc/ipc_channel_posix_unittest.cc

Index: ipc/ipc_channel_posix_unittest.cc
diff --git a/ipc/ipc_channel_posix_unittest.cc b/ipc/ipc_channel_posix_unittest.cc
index 834f0ea74487640e7a47f916fb384c08546ab456..bd4b7f7b7537024ab066ceee6b4880b27203967d 100644
--- a/ipc/ipc_channel_posix_unittest.cc
+++ b/ipc/ipc_channel_posix_unittest.cc
@@ -21,6 +21,7 @@
 #include "base/test/multiprocess_test.h"
 #include "base/test/test_timeouts.h"
 #include "ipc/ipc_listener.h"
+#include "ipc/ipc_tests.h"
 #include "testing/multiprocess_func_list.h"
 
 namespace {
@@ -391,7 +392,7 @@ TEST_F(IPCChannelPosixTest, IsNamedServerInitialized) {
 }
 
 // A long running process that connects to us
-MULTIPROCESS_TEST_MAIN(IPCChannelPosixTestConnectionProc) {
+MULTIPROCESS_IPC_TEST_MAIN(IPCChannelPosixTestConnectionProc) {
   MessageLoopForIO message_loop;
   IPCChannelPosixTestListener listener(true);
   IPC::ChannelHandle handle(IPCChannelPosixTest::GetConnectionSocketName());
@@ -404,7 +405,7 @@ MULTIPROCESS_TEST_MAIN(IPCChannelPosixTestConnectionProc) {
 }
 
 // Simple external process that shouldn't be able to connect to us.
-MULTIPROCESS_TEST_MAIN(IPCChannelPosixFailConnectionProc) {
+MULTIPROCESS_IPC_TEST_MAIN(IPCChannelPosixFailConnectionProc) {
   MessageLoopForIO message_loop;
   IPCChannelPosixTestListener listener(false);
   IPC::ChannelHandle handle(IPCChannelPosixTest::GetConnectionSocketName());