power save blocker: Don't try to block power saving in headless mode

device/power_save_blocker/power_save_blocker_x11.cc

 // Copyright (c) 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 <X11/Xlib.h>
 #include <X11/extensions/dpms.h>
 #include <X11/extensions/scrnsaver.h>
 #include <stdint.h>
 
 #include <memory>
@@ skipping 14 matching lines @@
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/singleton.h"
 #include "base/nix/xdg_util.h"
 #include "base/synchronization/lock.h"
 #include "dbus/bus.h"
 #include "dbus/message.h"
 #include "dbus/object_path.h"
 #include "dbus/object_proxy.h"
+#include "ui/gfx/switches.h"
 #include "ui/gfx/x/x11_types.h"
 
 namespace {
 
 enum DBusAPI {
   NO_API,           // Disable. No supported API available.
   GNOME_API,        // Use the GNOME API. (Supports more features.)
   FREEDESKTOP_API,  // Use the FreeDesktop API, for KDE4, KDE5, and XFCE.
 };
 
@@ skipping 384 matching lines @@
   int dummy;
   if (DPMSQueryExtension(display, &dummy, &dummy) && DPMSCapable(display)) {
     CARD16 state;
     DPMSInfo(display, &state, &enabled);
   }
   return enabled;
 }
 
 bool PowerSaveBlocker::Delegate::XSSAvailable() {
   DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kHeadless))

[hashimoto, 2017/01/17 15:28:32]

Please add a brief comment to justify this behavior.

[Sami, 2017/01/17 15:43:49]

Done.

+    return false;
   XDisplay* display = gfx::GetXDisplay();
   int dummy;
   int major;
   int minor;
 
   if (!XScreenSaverQueryExtension(display, &dummy, &dummy))
     return false;
 
   if (!XScreenSaverQueryVersion(display, &major, &minor))
     return false;
 
   return major > 1 || (major == 1 && minor >= 1);
 }
 
 DBusAPI PowerSaveBlocker::Delegate::SelectAPI() {
   DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kHeadless))

[hashimoto, 2017/01/17 15:28:32]

ditto.

[Sami, 2017/01/17 15:43:49]

Done.

+    return NO_API;
   std::unique_ptr<base::Environment> env(base::Environment::Create());
   switch (base::nix::GetDesktopEnvironment(env.get())) {
     case base::nix::DESKTOP_ENVIRONMENT_GNOME:
     case base::nix::DESKTOP_ENVIRONMENT_UNITY:
       if (DPMSEnabled())
         return GNOME_API;
       break;
     case base::nix::DESKTOP_ENVIRONMENT_XFCE:
     case base::nix::DESKTOP_ENVIRONMENT_KDE4:
     case base::nix::DESKTOP_ENVIRONMENT_KDE5:
@@ skipping 31 matching lines @@
   }
 }
 
 PowerSaveBlocker::~PowerSaveBlocker() {
   delegate_->CleanUp();
   if (freedesktop_suspend_delegate_)
     freedesktop_suspend_delegate_->CleanUp();
 }
 
 }  // namespace device