Reland of Pass SequencedTaskRunner to PowerSaveBlocker for ui/file ops

content/browser/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>
 
 #include "content/browser/power_save_blocker_impl.h"
 // Xlib #defines Status, but we can't have that for some of our headers.
 #ifdef Status
 #undef Status
 #endif
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/environment.h"
 #include "base/files/file_path.h"
+#include "base/location.h"
 #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 "content/public/browser/browser_thread.h"
 #include "dbus/bus.h"
 #include "dbus/message.h"
 #include "dbus/object_path.h"
 #include "dbus/object_proxy.h"
 #include "ui/gfx/x/x11_types.h"
 
 namespace {
 
 enum DBusAPI {
   NO_API,           // Disable. No supported API available.
@@ skipping 29 matching lines @@
 }  // namespace
 
 namespace content {
 
 class PowerSaveBlockerImpl::Delegate
     : public base::RefCountedThreadSafe<PowerSaveBlockerImpl::Delegate> {
  public:
   // Picks an appropriate D-Bus API to use based on the desktop environment.
   Delegate(PowerSaveBlockerType type,
            const std::string& description,
-           bool freedesktop_only);
+           bool freedesktop_only,
+           scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
+           scoped_refptr<base::SingleThreadTaskRunner> blocking_task_runner);
 
   // Post a task to initialize the delegate on the UI thread, which will itself
   // then post a task to apply the power save block on the FILE thread.
   void Init();
 
   // Post a task to remove the power save block on the FILE thread, unless it
   // hasn't yet been applied, in which case we just prevent it from applying.
   void CleanUp();
 
  private:
@@ skipping 16 matching lines @@
   void RemoveBlock();
 
   // Asynchronous callback functions for ApplyBlock and RemoveBlock.
   // Functions do not receive ownership of |response|.
   void ApplyBlockFinished(dbus::Response* response);
   void RemoveBlockFinished(dbus::Response* response);
 
   // Wrapper for XScreenSaverSuspend. Checks whether the X11 Screen Saver
   // Extension is available first. If it isn't, this is a no-op.
   // Must be called on the UI thread.
-  static void XSSSuspendSet(bool suspend);
+  void XSSSuspendSet(bool suspend);
 
   // If DPMS (the power saving system in X11) is not enabled, then we don't want
   // to try to disable power saving, since on some desktop environments that may
   // enable DPMS with very poor default settings (e.g. turning off the display
   // after only 1 second). Must be called on the UI thread.
-  static bool DPMSEnabled();
+  bool DPMSEnabled();
 
   // If no other method is available (i.e. not running under a Desktop
   // Environment) check whether the X11 Screen Saver Extension can be used
   // to disable the screen saver. Must be called on the UI thread.
-  static bool XSSAvailable();
+  bool XSSAvailable();
 
   // Returns an appropriate D-Bus API to use based on the desktop environment.
   // Must be called on the UI thread, as it may call DPMSEnabled() above.
-  static DBusAPI SelectAPI();
+  DBusAPI SelectAPI();
 
   const PowerSaveBlockerType type_;
   const std::string description_;
   const bool freedesktop_only_;
 
   // Initially, we post a message to the UI thread to select an API. When it
   // finishes, it will post a message to the FILE thread to perform the actual
   // application of the block, unless enqueue_apply_ is false. We set it to
   // false when we post that message, or when RemoveBlock() is called before
   // ApplyBlock() has run. Both api_ and enqueue_apply_ are guarded by lock_.
   DBusAPI api_;
   bool enqueue_apply_;
   base::Lock lock_;
 
   // Indicates that a D-Bus power save blocking request is in flight.
   bool block_inflight_;
   // Used to detect erronous redundant calls to RemoveBlock().
   bool unblock_inflight_;
   // Indicates that RemoveBlock() is called before ApplyBlock() has finished.
   // If it's true, then the RemoveBlock() call will be processed immediately
   // after ApplyBlock() has finished.
   bool enqueue_unblock_;
 
   scoped_refptr<dbus::Bus> bus_;
 
   // The cookie that identifies our inhibit request,
   // or 0 if there is no active inhibit request.
   uint32_t inhibit_cookie_;
 
+  scoped_refptr<base::SequencedTaskRunner> ui_task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> blocking_task_runner_;
+
   DISALLOW_COPY_AND_ASSIGN(Delegate);
 };
 
-PowerSaveBlockerImpl::Delegate::Delegate(PowerSaveBlockerType type,
-                                         const std::string& description,
-                                         bool freedesktop_only)
+PowerSaveBlockerImpl::Delegate::Delegate(
+    PowerSaveBlockerType type,
+    const std::string& description,
+    bool freedesktop_only,
+    scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> blocking_task_runner)
     : type_(type),
       description_(description),
       freedesktop_only_(freedesktop_only),
       api_(NO_API),
       enqueue_apply_(false),
-      inhibit_cookie_(0) {
+      inhibit_cookie_(0),
+      ui_task_runner_(ui_task_runner),
+      blocking_task_runner_(blocking_task_runner) {
   // We're on the client's thread here, so we don't allocate the dbus::Bus
   // object yet. We'll do it later in ApplyBlock(), on the FILE thread.
 }
 
 void PowerSaveBlockerImpl::Delegate::Init() {
   base::AutoLock lock(lock_);
   DCHECK(!enqueue_apply_);
   enqueue_apply_ = true;
   block_inflight_ = false;
   unblock_inflight_ = false;
   enqueue_unblock_ = false;
-  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                          base::Bind(&Delegate::InitOnUIThread, this));
+  ui_task_runner_->PostTask(FROM_HERE,
+                            base::Bind(&Delegate::InitOnUIThread, this));
 }
 
 void PowerSaveBlockerImpl::Delegate::CleanUp() {
   base::AutoLock lock(lock_);
   if (enqueue_apply_) {
     // If a call to ApplyBlock() has not yet been enqueued because we are still
     // initializing on the UI thread, then just cancel it. We don't need to
     // remove the block because we haven't even applied it yet.
     enqueue_apply_ = false;
   } else {
     if (ShouldBlock()) {
-      BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
-                              base::Bind(&Delegate::RemoveBlock, this));
+      blocking_task_runner_->PostTask(FROM_HERE,
+                                      base::Bind(&Delegate::RemoveBlock, this));
     }
 
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                            base::Bind(&Delegate::XSSSuspendSet, false));
+    ui_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&Delegate::XSSSuspendSet, this, false));
   }
 }
 
 void PowerSaveBlockerImpl::Delegate::InitOnUIThread() {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
   base::AutoLock lock(lock_);
   api_ = SelectAPI();
 
   if (enqueue_apply_) {
     if (ShouldBlock()) {
       // The thread we use here becomes the origin and D-Bus thread for the
       // D-Bus library, so we need to use the same thread above for
       // RemoveBlock(). It must be a thread that allows I/O operations, so we
       // use the FILE thread.
-      BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
-                              base::Bind(&Delegate::ApplyBlock, this));
+      blocking_task_runner_->PostTask(FROM_HERE,
+                                      base::Bind(&Delegate::ApplyBlock, this));
     }
     XSSSuspendSet(true);
   }
   enqueue_apply_ = false;
 }
 
 bool PowerSaveBlockerImpl::Delegate::ShouldBlock() const {
   return freedesktop_only_ ? api_ == FREEDESKTOP_API : api_ != NO_API;
 }
 
 void PowerSaveBlockerImpl::Delegate::ApplyBlock() {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK(blocking_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(!bus_);  // ApplyBlock() should only be called once.
   DCHECK(!block_inflight_);
 
   dbus::Bus::Options options;
   options.bus_type = dbus::Bus::SESSION;
   options.connection_type = dbus::Bus::PRIVATE;
   bus_ = new dbus::Bus(options);
 
   scoped_refptr<dbus::ObjectProxy> object_proxy;
   std::unique_ptr<dbus::MethodCall> method_call;
@@ skipping 61 matching lines @@
   }
 
   block_inflight_ = true;
   object_proxy->CallMethod(
       method_call.get(), dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
       base::Bind(&PowerSaveBlockerImpl::Delegate::ApplyBlockFinished, this));
 }
 
 void PowerSaveBlockerImpl::Delegate::ApplyBlockFinished(
     dbus::Response* response) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK(blocking_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(bus_);
   DCHECK(block_inflight_);
   block_inflight_ = false;
 
   if (response) {
     // The method returns an inhibit_cookie, used to uniquely identify
     // this request. It should be used as an argument to Uninhibit()
     // in order to remove the request.
     dbus::MessageReader message_reader(response);
     if (!message_reader.PopUint32(&inhibit_cookie_))
       LOG(ERROR) << "Invalid Inhibit() response: " << response->ToString();
   } else {
     LOG(ERROR) << "No response to Inhibit() request!";
   }
 
   if (enqueue_unblock_) {
     enqueue_unblock_ = false;
     // RemoveBlock() was called while the Inhibit operation was in flight,
     // so go ahead and remove the block now.
-    BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
-                            base::Bind(&Delegate::RemoveBlock, this));
+    blocking_task_runner_->PostTask(FROM_HERE,
+                                    base::Bind(&Delegate::RemoveBlock, this));
   }
 }
 
 void PowerSaveBlockerImpl::Delegate::RemoveBlock() {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK(blocking_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(bus_);  // RemoveBlock() should only be called once.
   DCHECK(!unblock_inflight_);
 
   if (block_inflight_) {
     DCHECK(!enqueue_unblock_);
     // Can't call RemoveBlock until ApplyBlock's async operation has
     // finished. Enqueue it for execution once ApplyBlock is done.
     enqueue_unblock_ = true;
     return;
   }
@@ skipping 35 matching lines @@
   dbus::MessageWriter message_writer(method_call.get());
   message_writer.AppendUint32(inhibit_cookie_);
   unblock_inflight_ = true;
   object_proxy->CallMethod(
       method_call.get(), dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
       base::Bind(&PowerSaveBlockerImpl::Delegate::RemoveBlockFinished, this));
 }
 
 void PowerSaveBlockerImpl::Delegate::RemoveBlockFinished(
     dbus::Response* response) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK(blocking_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(bus_);
   unblock_inflight_ = false;
 
   if (!response)
     LOG(ERROR) << "No response to Uninhibit() request!";
   // We don't care about checking the result. We assume it works; we can't
   // really do anything about it anyway if it fails.
   inhibit_cookie_ = 0;
 
   bus_->ShutdownAndBlock();
   bus_ = nullptr;
 }
 
-// static
 void PowerSaveBlockerImpl::Delegate::XSSSuspendSet(bool suspend) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
 
   if (!XSSAvailable())
     return;
 
   XDisplay* display = gfx::GetXDisplay();
   XScreenSaverSuspend(display, suspend);
 }
 
-// static
 bool PowerSaveBlockerImpl::Delegate::DPMSEnabled() {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
   XDisplay* display = gfx::GetXDisplay();
   BOOL enabled = false;
   int dummy;
   if (DPMSQueryExtension(display, &dummy, &dummy) && DPMSCapable(display)) {
     CARD16 state;
     DPMSInfo(display, &state, &enabled);
   }
   return enabled;
 }
 
-// static
 bool PowerSaveBlockerImpl::Delegate::XSSAvailable() {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
   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);
 }
 
-// static
 DBusAPI PowerSaveBlockerImpl::Delegate::SelectAPI() {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
   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:
       if (DPMSEnabled())
         return FREEDESKTOP_API;
       break;
     case base::nix::DESKTOP_ENVIRONMENT_KDE3:
     case base::nix::DESKTOP_ENVIRONMENT_OTHER:
       // Not supported.
       break;
   }
   return NO_API;
 }
 
-PowerSaveBlockerImpl::PowerSaveBlockerImpl(PowerSaveBlockerType type,
-                                           Reason reason,
-                                           const std::string& description)
-    : delegate_(new Delegate(type, description, false /* freedesktop_only */)) {
+PowerSaveBlockerImpl::PowerSaveBlockerImpl(
+    PowerSaveBlockerType type,
+    Reason reason,
+    const std::string& description,
+    scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> blocking_task_runner)
+    : delegate_(new Delegate(type,
+                             description,
+                             false /* freedesktop_only */,
+                             ui_task_runner,
+                             blocking_task_runner)),
+      ui_task_runner_(ui_task_runner),
+      blocking_task_runner_(blocking_task_runner) {
   delegate_->Init();
 
   if (type == kPowerSaveBlockPreventDisplaySleep) {
-    freedesktop_suspend_delegate_ =
-        new Delegate(kPowerSaveBlockPreventAppSuspension, description,
-                     true /* freedesktop_only */);
+    freedesktop_suspend_delegate_ = new Delegate(
+        kPowerSaveBlockPreventAppSuspension, description,
+        true /* freedesktop_only */, ui_task_runner, blocking_task_runner);
     freedesktop_suspend_delegate_->Init();
   }
 }
 
 PowerSaveBlockerImpl::~PowerSaveBlockerImpl() {
   delegate_->CleanUp();
   if (freedesktop_suspend_delegate_)
     freedesktop_suspend_delegate_->CleanUp();
 }
 
 }  // namespace content