Bug 1289678 - Don't count audio stream creation failures when retrying on Telemetry. r=kinetik

When failing to create an audio stream, we fallback to a SystemClockDriver
marked as being a "fallback driver". When failing again to open an audio stream
after re-trying, we can check whether we came from a fallback driver, and not
report the failure again to telemetry.

MozReview-Commit-ID: FAdQ0pCtC3m

dom/media/GraphDriver.cpp

@@ -294,12 +294,25 @@ ThreadedDriver::Stop()
 SystemClockDriver::SystemClockDriver(MediaStreamGraphImpl* aGraphImpl)
   : ThreadedDriver(aGraphImpl),
     mInitialTimeStamp(TimeStamp::Now()),
-    mLastTimeStamp(TimeStamp::Now())
+    mLastTimeStamp(TimeStamp::Now()),
+    mIsFallback(false)
 {}
 
 SystemClockDriver::~SystemClockDriver()
 { }
 
+void
+SystemClockDriver::MarkAsFallback()
+{
+  mIsFallback = true;
+}
+
+bool
+SystemClockDriver::IsFallback()
+{
+  return mIsFallback;
+}
+
 void
 ThreadedDriver::RunThread()
 {
@@ -545,6 +558,7 @@ AudioCallbackDriver::AudioCallbackDriver(MediaStreamGraphImpl* aGraphImpl)
   , mAddedMixer(false)
   , mInCallback(false)
   , mMicrophoneActive(false)
+  , mFromFallback(false)
 {
   STREAM_LOG(LogLevel::Debug, ("AudioCallbackDriver ctor for graph %p", aGraphImpl));
 }
@@ -636,13 +650,20 @@ AudioCallbackDriver::Init()
       StaticMutexAutoUnlock unlock(AudioInputCubeb::Mutex());
 #endif
       NS_WARNING("Could not create a cubeb stream for MediaStreamGraph, falling back to a SystemClockDriver");
-      CubebUtils::ReportCubebStreamInitFailure(firstStream);
+      // Only report failures when we're not coming from a driver that was
+      // created itself as a fallback driver because of a previous audio driver
+      // failure.
+      if (!mFromFallback) {
+        CubebUtils::ReportCubebStreamInitFailure(firstStream);
+      }
       // Fall back to a driver using a normal thread.
       MonitorAutoLock lock(GraphImpl()->GetMonitor());
-      SetNextDriver(new SystemClockDriver(GraphImpl()));
-      NextDriver()->SetGraphTime(this, mIterationStart, mIterationEnd);
-      mGraphImpl->SetCurrentDriver(NextDriver());
-      NextDriver()->Start();
+      SystemClockDriver* nextDriver = new SystemClockDriver(GraphImpl());
+      SetNextDriver(nextDriver);
+      nextDriver->MarkAsFallback();
+      nextDriver->SetGraphTime(this, mIterationStart, mIterationEnd);
+      mGraphImpl->SetCurrentDriver(nextDriver);
+      nextDriver->Start();
       return;
     }
   }
@@ -689,6 +710,8 @@ AudioCallbackDriver::Start()
       mPreviousDriver = nullptr;
     } else {
       LIFECYCLE_LOG("Dropping driver reference for SystemClockDriver.");
+      MOZ_ASSERT(mPreviousDriver->AsSystemClockDriver());
+      mFromFallback = mPreviousDriver->AsSystemClockDriver()->IsFallback();
       mPreviousDriver = nullptr;
     }
   }

dom/media/GraphDriver.h

@@ -54,6 +54,7 @@ class MediaStreamGraphImpl;
 
 class AudioCallbackDriver;
 class OfflineClockDriver;
+class SystemClockDriver;
 
 /**
  * A driver is responsible for the scheduling of the processing, the thread
@@ -165,6 +166,10 @@ public:
     return nullptr;
   }
 
+  virtual SystemClockDriver* AsSystemClockDriver() {
+    return nullptr;
+  }
+
   /**
    * Tell the driver it has to stop and return the current time of the graph, so
    * another driver can start from the right point in time.
@@ -296,13 +301,20 @@ public:
   MediaTime GetIntervalForIteration() override;
   void WaitForNextIteration() override;
   void WakeUp() override;
-
+  void MarkAsFallback();
+  bool IsFallback();
+  SystemClockDriver* AsSystemClockDriver() {
+    return this;
+  }
 
 private:
   // Those are only modified (after initialization) on the graph thread. The
   // graph thread does not run during the initialization.
   TimeStamp mInitialTimeStamp;
   TimeStamp mLastTimeStamp;
+  // This is true if this SystemClockDriver runs the graph because we could not
+  // open an audio stream.
+  bool mIsFallback;
 };
 
 /**
@@ -525,6 +537,9 @@ private:
    * True if microphone is being used by this process. This is synchronized by
    * the graph's monitor. */
   bool mMicrophoneActive;
+  /* True if this driver was created from a driver created because of a previous
+   * AudioCallbackDriver failure. */
+  bool mFromFallback;
 };
 
 class AsyncCubebTask : public Runnable