Add a microsecond timer from the start of the process

renderdoc/common/timing.h

@@ -41,6 +41,10 @@ public:
   {
     return double(Timing::GetTick() - m_Start) / m_CounterFrequency;
   }
+  double GetMicroseconds() const
+  {
+    return (double(Timing::GetTick() - m_Start) * 1000.0) / m_CounterFrequency;
+  }
 
   void Restart() { m_Start = Timing::GetTick(); }
 private:

renderdoc/core/core.h

@@ -205,6 +205,7 @@ public:
   void Initialise();
   void Shutdown();
 
+  uint64_t GetMicrosecondTimestamp() { return uint64_t(m_Timer.GetMicroseconds()); }
   const GlobalEnvironment GetGlobalEnvironment() { return m_GlobalEnv; }
   void ProcessGlobalEnvironment(GlobalEnvironment env, const std::vector<std::string> &args);
 
@@ -450,6 +451,8 @@ private:
   Threading::CriticalSection m_SingleClientLock;
   string m_SingleClientName;
 
+  PerformanceTimer m_Timer;
+
   static void TargetControlServerThread(Network::Socket *sock);
   static void TargetControlClientThread(Network::Socket *client);