Allow backgrounding processes on Mac

base/process/process_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/process/process.h"
 
 #include <utility>
 
 #include "base/process/kill.h"
 #include "base/test/multiprocess_test.h"
 #include "base/test/test_timeouts.h"
 #include "base/threading/platform_thread.h"
 #include "build/build_config.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/multiprocess_func_list.h"
 
 namespace {
 
 #if defined(OS_WIN)
 const int kExpectedStillRunningExitCode = 0x102;
 #else
 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 {
 
 class ProcessTest : public MultiProcessTest {
 };
 
 TEST_F(ProcessTest, Create) {
   Process process(SpawnChild("SimpleChildProcess"));
   ASSERT_TRUE(process.IsValid());
@@ skipping 129 matching lines @@
   EXPECT_EQ(kDummyExitCode, exit_code);
 
   process.Terminate(kDummyExitCode, false);
 }
 
 // Ensure that the priority of a process is restored correctly after
 // backgrounding and restoring.
 // 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)
   EXPECT_TRUE(process.SetProcessBackgrounded(true));
   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);
 }
 
 // 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)
   EXPECT_TRUE(process.SetProcessBackgrounded(true));
   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);
 #endif
   int new_priority = process.GetPriority();
   EXPECT_EQ(old_priority, new_priority);
 }
 
 #if defined(OS_CHROMEOS)
 
 // Tests that the function IsProcessBackgroundedCGroup() can parse the contents
 // of the /proc/<pid>/cgroup file successfully.
 TEST_F(ProcessTest, TestIsProcessBackgroundedCGroup) {
   const char kNotBackgrounded[] = "5:cpuacct,cpu,cpuset:/daemons\n";
   const char kBackgrounded[] =
       "2:freezer:/chrome_renderers/to_be_frozen\n"
       "1:cpu:/chrome_renderers/background\n";
 
   EXPECT_FALSE(IsProcessBackgroundedCGroup(kNotBackgrounded));
   EXPECT_TRUE(IsProcessBackgroundedCGroup(kBackgrounded));
 }
 
 #endif  // defined(OS_CHROMEOS)
 
 }  // namespace base