vcl: assert solar mutex is held for various timer / scheduler ops.

Bringing paranoia to some source-code near you.

Change-Id: I92bc1e17480405a6388c2cbd1c7b559728539f67
Reviewed-on: https://gerrit.libreoffice.org/30024Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>

vcl/source/app/scheduler.cxx

@@ -31,6 +31,8 @@ void InitSystemTimer(ImplSVData* pSVData);
 
 void ImplSchedulerData::Invoke()
 {
+    DBG_TESTSOLARMUTEX();
+
     if (mbDelete || mbInScheduler )
         return;
 
@@ -127,6 +129,9 @@ void Scheduler::ImplStartTimer(sal_uInt64 nMS, bool bForce)
         // ImplSalStopTimer() on WNT the timer queue is restarted and never ends
         return;
     }
+
+    DBG_TESTSOLARMUTEX();
+
     InitSystemTimer(pSVData);
 
     if ( !nMS )
@@ -169,6 +174,8 @@ bool Scheduler::ProcessTaskScheduling( bool bTimerOnly )
 {
     ImplSchedulerData* pSchedulerData;
 
+    DBG_TESTSOLARMUTEX();
+
     if ((pSchedulerData = ImplSchedulerData::GetMostImportantTask(bTimerOnly)))
     {
         SAL_INFO("vcl.schedule", "Invoke task " << pSchedulerData->GetDebugName());
@@ -203,6 +210,8 @@ sal_uInt64 Scheduler::CalculateMinimumTimeout( bool &bHasActiveIdles )
     sal_uInt64         nTime = tools::Time::GetSystemTicks();
     sal_uInt64         nMinPeriod = MaximumTimeoutMs;
 
+    DBG_TESTSOLARMUTEX();
+
     SAL_INFO("vcl.schedule", "Calculating minimum timeout:");
     pSchedulerData = pSVData->mpFirstSchedulerData;
     while ( pSchedulerData )
@@ -275,6 +284,8 @@ void Scheduler::Start()
         return;
     }
 
+    DBG_TESTSOLARMUTEX();
+
     // Mark timer active
     mbActive = true;