Attempting to resolve a race condition with PowerMonitor.

ThreadSanitizer caught multiple instances where PowerMonitor::Get or PowerMonitor::Add/RemoveObserver were being called concurrently with the PowerMonitor constructor in the main thread. These functions access a process-global PowerMontior instance (g_power_monitor), which was not thread safe.

This change adds locks around PowerMonitor creation and deletion, and forces Add/RemoveObserver to be called in a threadsafe manner. It also removes the need to call PowerMonitor::Get.

BUG=268924

Review URL: https://codereview.chromium.org/179923006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@262018 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 3 insertions, 3 deletions

diff --git a/media/audio/mac/audio_manager_mac.cc b/media/audio/mac/audio_manager_mac.cc
index 60c8a3e..b9376447 100644
--- a/media/audio/mac/audio_manager_mac.cc
+++ b/media/audio/mac/audio_manager_mac.cc
@@ -226,20 +226,20 @@ class AudioManagerMac::AudioPowerObserver : public base::PowerObserver {
  public:
   AudioPowerObserver()
       : is_suspending_(false),
-        is_monitoring_(base::PowerMonitor::Get()) {
+        is_monitoring_(base::PowerMonitor::IsInitialized()) {
     // The PowerMonitor requires signifcant setup (a CFRunLoop and preallocated
     // IO ports) so it's not available under unit tests.  See the OSX impl of
     // base::PowerMonitorDeviceSource for more details.
     if (!is_monitoring_)
       return;
-    base::PowerMonitor::Get()->AddObserver(this);
+    base::PowerMonitor::AddObserver(this);
   }
 
   virtual ~AudioPowerObserver() {
     DCHECK(thread_checker_.CalledOnValidThread());
     if (!is_monitoring_)
       return;
-    base::PowerMonitor::Get()->RemoveObserver(this);
+    base::PowerMonitor::RemoveObserver(this);
   }
 
   bool ShouldDeferOutputStreamStart() {