Allow backgrounding processes on Mac

base/process/process_unittest.cc

Index: base/process/process_unittest.cc
diff --git a/base/process/process_unittest.cc b/base/process/process_unittest.cc
index 853f1fe8fff4895d6a749333b6818651861c6312..90bb95a0fe9b04964cedb716629bb42e3058741f 100644
--- a/base/process/process_unittest.cc
+++ b/base/process/process_unittest.cc
@@ -22,6 +22,16 @@ const int kExpectedStillRunningExitCode = 0x102;
 const int kExpectedStillRunningExitCode = 0;
 #endif
 
+#if defined(OS_MACOSX)
+// Fake port provider that returns the calling process's
+// task port, ignoring its argument.
+class FakePortProvider : public base::PortProvider {
+  mach_port_t TaskForPid(base::ProcessHandle process) const override {
+    return mach_task_self();
+  }
+};
+#endif
+
 }  // namespace
 
 namespace base {
@@ -171,6 +181,8 @@ TEST_F(ProcessTest, WaitForExitWithTimeout) {
 // Note: a platform may not be willing or able to lower the priority of
 // a process. The calls to SetProcessBackground should be noops then.
 TEST_F(ProcessTest, SetProcessBackgrounded) {
+  if (!Process::CanBackgroundProcesses())
+    return;
   Process process(SpawnChild("SimpleChildProcess"));
   int old_priority = process.GetPriority();
 #if defined(OS_WIN)
@@ -178,11 +190,22 @@ TEST_F(ProcessTest, SetProcessBackgrounded) {
   EXPECT_TRUE(process.IsProcessBackgrounded());
   EXPECT_TRUE(process.SetProcessBackgrounded(false));
   EXPECT_FALSE(process.IsProcessBackgrounded());
+#elif defined(OS_MACOSX)
+  // On the Mac, backgrounding a process requires a port to that process.
+  // In the browser it's available through the MachBroker class, which is not
+  // part of base. Additionally, there is an indefinite amount of time between
+  // spawning a process and receiving its port. Because this test just checks
+  // the ability to background/foreground a process, we can use the current
+  // process's port instead.
+  FakePortProvider provider;
+  EXPECT_TRUE(process.SetProcessBackgrounded(&provider, true));
+  EXPECT_TRUE(process.IsProcessBackgrounded(&provider));
+  EXPECT_TRUE(process.SetProcessBackgrounded(&provider, false));
+  EXPECT_FALSE(process.IsProcessBackgrounded(&provider));
+
 #else
-  if (process.CanBackgroundProcesses()) {
-    process.SetProcessBackgrounded(true);
-    process.SetProcessBackgrounded(false);
-  }
+  process.SetProcessBackgrounded(true);
+  process.SetProcessBackgrounded(false);
 #endif
   int new_priority = process.GetPriority();
   EXPECT_EQ(old_priority, new_priority);
@@ -191,6 +214,8 @@ TEST_F(ProcessTest, SetProcessBackgrounded) {
 // Same as SetProcessBackgrounded but to this very process. It uses
 // a different code path at least for Windows.
 TEST_F(ProcessTest, SetProcessBackgroundedSelf) {
+  if (!Process::CanBackgroundProcesses())
+    return;
   Process process = Process::Current();
   int old_priority = process.GetPriority();
 #if defined(OS_WIN)
@@ -198,6 +223,12 @@ TEST_F(ProcessTest, SetProcessBackgroundedSelf) {
   EXPECT_TRUE(process.IsProcessBackgrounded());
   EXPECT_TRUE(process.SetProcessBackgrounded(false));
   EXPECT_FALSE(process.IsProcessBackgrounded());
+#elif defined(OS_MACOSX)
+  FakePortProvider provider;
+  EXPECT_TRUE(process.SetProcessBackgrounded(&provider, true));
+  EXPECT_TRUE(process.IsProcessBackgrounded(&provider));
+  EXPECT_TRUE(process.SetProcessBackgrounded(&provider, false));
+  EXPECT_FALSE(process.IsProcessBackgrounded(&provider));
 #else
   process.SetProcessBackgrounded(true);
   process.SetProcessBackgrounded(false);