Check dbus response for null before using. (#15088)

Fixes #14958.

Manual backport of #15030. Drops some the BindOnce improvements
due to compile issues with older version of Chromium.

atom/browser/lib/power_observer_linux.cc

@@ -6,6 +6,7 @@
 #include <unistd.h>
 #include <uv.h>
 #include <iostream>
+#include <utility>
 
 #include "base/bind.h"
 #include "device/bluetooth/dbus/dbus_thread_manager_linux.h"
@@ -23,7 +24,7 @@ std::string get_executable_basename() {
   if (!uv_exepath(buf, &buf_size)) {
     rv = strrchr(static_cast<const char*>(buf), '/') + 1;
   }
-  return std::move(rv);
+  return rv;
 }
 
 }  // namespace
@@ -32,39 +33,37 @@ namespace atom {
 
 PowerObserverLinux::PowerObserverLinux()
     : lock_owner_name_(get_executable_basename()), weak_ptr_factory_(this) {
-  auto dbus_thread_manager = bluez::DBusThreadManagerLinux::Get();
-  if (dbus_thread_manager) {
-    bus_ = dbus_thread_manager->GetSystemBus();
-    if (bus_) {
-      logind_ = bus_->GetObjectProxy(kLogindServiceName,
-                                     dbus::ObjectPath(kLogindObjectPath));
-      logind_->WaitForServiceToBeAvailable(
-          base::Bind(&PowerObserverLinux::OnLoginServiceAvailable,
-                     weak_ptr_factory_.GetWeakPtr()));
-    } else {
-      LOG(WARNING) << "Failed to get system bus connection";
-    }
-  } else {
-    LOG(WARNING) << "DBusThreadManagerLinux instance isn't available";
+  auto* bus = bluez::DBusThreadManagerLinux::Get()->GetSystemBus();
+  if (!bus) {
+    LOG(WARNING) << "Failed to get system bus connection";
+    return;
   }
+
+  // set up the logind proxy
+
+  const auto weakThis = weak_ptr_factory_.GetWeakPtr();
+
+  logind_ = bus->GetObjectProxy(kLogindServiceName,
+                                dbus::ObjectPath(kLogindObjectPath));
+  logind_->ConnectToSignal(
+      kLogindManagerInterface, "PrepareForShutdown",
+      base::BindRepeating(&PowerObserverLinux::OnPrepareForShutdown, weakThis),
+      base::BindRepeating(&PowerObserverLinux::OnSignalConnected, weakThis));
+  logind_->ConnectToSignal(
+      kLogindManagerInterface, "PrepareForSleep",
+      base::BindRepeating(&PowerObserverLinux::OnPrepareForSleep, weakThis),
+      base::BindRepeating(&PowerObserverLinux::OnSignalConnected, weakThis));
+  logind_->WaitForServiceToBeAvailable(base::BindRepeating(
+      &PowerObserverLinux::OnLoginServiceAvailable, weakThis));
 }
 
+PowerObserverLinux::~PowerObserverLinux() = default;
+
 void PowerObserverLinux::OnLoginServiceAvailable(bool service_available) {
   if (!service_available) {
     LOG(WARNING) << kLogindServiceName << " not available";
     return;
   }
-  // Connect to PrepareForShutdown/PrepareForSleep signals
-  logind_->ConnectToSignal(kLogindManagerInterface, "PrepareForShutdown",
-                           base::Bind(&PowerObserverLinux::OnPrepareForShutdown,
-                                      weak_ptr_factory_.GetWeakPtr()),
-                           base::Bind(&PowerObserverLinux::OnSignalConnected,
-                                      weak_ptr_factory_.GetWeakPtr()));
-  logind_->ConnectToSignal(kLogindManagerInterface, "PrepareForSleep",
-                           base::Bind(&PowerObserverLinux::OnPrepareForSleep,
-                                      weak_ptr_factory_.GetWeakPtr()),
-                           base::Bind(&PowerObserverLinux::OnSignalConnected,
-                                      weak_ptr_factory_.GetWeakPtr()));
   // Take sleep inhibit lock
   BlockSleep();
 }
@@ -120,8 +119,10 @@ void PowerObserverLinux::SetShutdownHandler(base::Callback<bool()> handler) {
 
 void PowerObserverLinux::OnInhibitResponse(base::ScopedFD* scoped_fd,
                                            dbus::Response* response) {
-  dbus::MessageReader reader(response);
-  reader.PopFileDescriptor(scoped_fd);
+  if (response != nullptr) {
+    dbus::MessageReader reader(response);
+    reader.PopFileDescriptor(scoped_fd);
+  }
 }
 
 void PowerObserverLinux::OnPrepareForSleep(dbus::Signal* signal) {
@@ -156,7 +157,7 @@ void PowerObserverLinux::OnPrepareForShutdown(dbus::Signal* signal) {
   }
 }
 
-void PowerObserverLinux::OnSignalConnected(const std::string& interface,
+void PowerObserverLinux::OnSignalConnected(const std::string& /*interface*/,
                                            const std::string& signal,
                                            bool success) {
   LOG_IF(WARNING, !success) << "Failed to connect to " << signal;

atom/browser/lib/power_observer_linux.h

@@ -19,6 +19,7 @@ namespace atom {
 class PowerObserverLinux : public base::PowerObserver {
  public:
   PowerObserverLinux();
+  ~PowerObserverLinux() override;
 
  protected:
   void BlockSleep();
@@ -39,7 +40,6 @@ class PowerObserverLinux : public base::PowerObserver {
 
   base::Callback<bool()> should_shutdown_;
 
-  scoped_refptr<dbus::Bus> bus_;
   scoped_refptr<dbus::ObjectProxy> logind_;
   std::string lock_owner_name_;
   base::ScopedFD sleep_lock_;