Allow backgrounding processes on Mac

content/browser/child_process_launcher.cc

 // Copyright 2012 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 "content/browser/child_process_launcher.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 20 matching lines @@
 #include "mojo/edk/embedder/scoped_platform_handle.h"
 
 #if defined(OS_WIN)
 #include "base/files/file_path.h"
 #include "base/win/scoped_handle.h"
 #include "base/win/win_util.h"
 #include "content/common/sandbox_win.h"
 #include "content/public/common/sandbox_init.h"
 #include "sandbox/win/src/sandbox_types.h"
 #elif defined(OS_MACOSX)
+#include "base/feature_list.h"
 #include "content/browser/bootstrap_sandbox_manager_mac.h"
 #include "content/browser/mach_broker_mac.h"
+#include "content/public/common/content_features.h"
 #include "sandbox/mac/bootstrap_sandbox.h"
 #include "sandbox/mac/pre_exec_delegate.h"
 #elif defined(OS_ANDROID)
 #include "base/android/jni_android.h"
 #include "content/browser/android/child_process_launcher_android.h"
 #elif defined(OS_POSIX)
 #include "base/memory/singleton.h"
 #include "content/browser/renderer_host/render_sandbox_host_linux.h"
 #include "content/browser/zygote_host/zygote_communication_linux.h"
 #include "content/browser/zygote_host/zygote_host_impl_linux.h"
@@ skipping 325 matching lines @@
 #endif  // !OS_MACOSX
     base::EnsureProcessTerminated(std::move(process));
 #endif  // OS_POSIX
 #endif  // defined(OS_ANDROID)
 }
 
 void SetProcessBackgroundedOnLauncherThread(base::Process process,
                                             bool background) {
   DCHECK_CURRENTLY_ON(BrowserThread::PROCESS_LAUNCHER);
   if (process.CanBackgroundProcesses()) {
+#if defined(OS_MACOSX)
+    if (base::FeatureList::IsEnabled(features::kMacBackgroundInactiveTabs))

[shrike, 2016/10/31 17:26:05]

Is this the only place you need to check for the experiment being enabled? I
think UpdateProcessPriority(), for example, can get called from a few different
places and would need this check.

I feel like I remember the experiment check living in SetProcessBackgrounded()
previously, but I guess that won't work with a content feature? If it's possible
to live in SetProcessBackgrounded() (or CanBackgroundProcesses() ) that might be
a better place, so that you have a single chokepoint for calls to background the
process.

 

[lgrey, 2016/10/31 19:22:02]

Moved to CanBackgroundProcesses and moved the feature definition to process. The
only reason I had it in content_features is that's where it seemed like it
belonged if the usage was in content.

+      process.SetProcessBackgrounded(MachBroker::GetInstance(), background);
+#else
     process.SetProcessBackgrounded(background);
+#endif  // defined(OS_MACOSX)
   }
 #if defined(OS_ANDROID)
   SetChildProcessInForeground(process.Handle(), !background);
 #endif
 }
 
 }  // namespace
 
 ChildProcessLauncher::ChildProcessLauncher(
     SandboxedProcessLauncherDelegate* delegate,
@@ skipping 223 matching lines @@
 }
 
 ChildProcessLauncher::Client* ChildProcessLauncher::ReplaceClientForTest(
     Client* client) {
   Client* ret = client_;
   client_ = client;
   return ret;
 }
 
 }  // namespace content