Bug 1226826 - Record if painted displayport updates were due to repaints from the relevant layer tree or not. r=botond

--HG--
extra : commitid : L42zD9MDNXD

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -455,8 +455,8 @@ APZCTreeManager::PrepareNodeForLayer(const LayerMetricsWrapper& aLayer,
 
     APZCTM_LOG("Using APZC %p for layer %p with identifiers %" PRId64 " %" PRId64 "\n", apzc, aLayer.GetLayer(), aLayersId, aMetrics.GetScrollId());
 
-    apzc->NotifyLayersUpdated(aMetrics,
-        aState.mIsFirstPaint && (aLayersId == aState.mOriginatingLayersId));
+    apzc->NotifyLayersUpdated(aMetrics, aState.mIsFirstPaint,
+        aLayersId == aState.mOriginatingLayersId);
 
     // Since this is the first time we are encountering an APZC with this guid,
     // the node holding it must be the primary holder. It may be newly-created

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -3137,7 +3137,10 @@ bool AsyncPanZoomController::IsCurrentlyCheckerboarding() const {
   return true;
 }
 
-void AsyncPanZoomController::NotifyLayersUpdated(const FrameMetrics& aLayerMetrics, bool aIsFirstPaint) {
+void AsyncPanZoomController::NotifyLayersUpdated(const FrameMetrics& aLayerMetrics,
+                                                 bool aIsFirstPaint,
+                                                 bool aThisLayerTreeUpdated)
+{
   APZThreadUtils::AssertOnCompositorThread();
 
   ReentrantMonitorAutoEnter lock(mMonitor);
@@ -3146,15 +3149,28 @@ void AsyncPanZoomController::NotifyLayersUpdated(const FrameMetrics& aLayerMetri
   mLastContentPaintMetrics = aLayerMetrics;
 
   mFrameMetrics.SetScrollParentId(aLayerMetrics.GetScrollParentId());
-  APZC_LOG_FM(aLayerMetrics, "%p got a NotifyLayersUpdated with aIsFirstPaint=%d", this, aIsFirstPaint);
+  APZC_LOG_FM(aLayerMetrics, "%p got a NotifyLayersUpdated with aIsFirstPaint=%d, aThisLayerTreeUpdated=%d",
+    this, aIsFirstPaint, aThisLayerTreeUpdated);
 
   if (mCheckerboardEvent) {
     std::string str;
-    if (!aLayerMetrics.GetPaintRequestTime().IsNull()) {
-      TimeDuration paintTime = TimeStamp::Now() - aLayerMetrics.GetPaintRequestTime();
-      std::stringstream info;
-      info << " painttime " << paintTime.ToMilliseconds();
-      str = info.str();
+    if (aThisLayerTreeUpdated) {
+      if (!aLayerMetrics.GetPaintRequestTime().IsNull()) {
+        // Note that we might get the paint request time as non-null, but with
+        // aThisLayerTreeUpdated false. That can happen if we get a layer transaction
+        // from a different process right after we get the layer transaction with
+        // aThisLayerTreeUpdated == true. In this case we want to ignore the
+        // paint request time because it was already dumped in the previous layer
+        // transaction.
+        TimeDuration paintTime = TimeStamp::Now() - aLayerMetrics.GetPaintRequestTime();
+        std::stringstream info;
+        info << " painttime " << paintTime.ToMilliseconds();
+        str = info.str();
+      } else {
+        // This might be indicative of a wasted paint particularly if it happens
+        // during a checkerboard event.
+        str = " (this layertree updated)";
+      }
     }
     mCheckerboardEvent->UpdateRendertraceProperty(
         CheckerboardEvent::Page, aLayerMetrics.GetScrollableRect());
@@ -3196,7 +3212,7 @@ void AsyncPanZoomController::NotifyLayersUpdated(const FrameMetrics& aLayerMetri
   // TODO if we're in a drag and scrollOffsetUpdated is set then we want to
   // ignore it
 
-  if (aIsFirstPaint || isDefault) {
+  if ((aIsFirstPaint && aThisLayerTreeUpdated) || isDefault) {
     // Initialize our internal state to something sane when the content
     // that was just painted is something we knew nothing about previously
     CancelAnimation();

gfx/layers/apz/src/AsyncPanZoomController.h

@@ -183,7 +183,8 @@ public:
    * layers code indicating that the frame metrics being sent with this call are
    * the initial metrics and the initial paint of the frame has just happened.
    */
-  void NotifyLayersUpdated(const FrameMetrics& aLayerMetrics, bool aIsFirstPaint);
+  void NotifyLayersUpdated(const FrameMetrics& aLayerMetrics, bool aIsFirstPaint,
+                           bool aThisLayerTreeUpdated);
 
   /**
    * The platform implementation must set the compositor parent so that we can

gfx/layers/apz/test/gtest/TestAsyncPanZoomController.cpp

@@ -1181,13 +1181,13 @@ TEST_F(APZCBasicTester, ComplexTransform) {
 
   // initial transform
   apzc->SetFrameMetrics(metrics);
-  apzc->NotifyLayersUpdated(metrics, true);
+  apzc->NotifyLayersUpdated(metrics, true, true);
   apzc->SampleContentTransformForFrame(&viewTransformOut, pointOut);
   EXPECT_EQ(AsyncTransform(LayerToParentLayerScale(1), ParentLayerPoint()), viewTransformOut);
   EXPECT_EQ(ParentLayerPoint(60, 60), pointOut);
 
   childApzc->SetFrameMetrics(childMetrics);
-  childApzc->NotifyLayersUpdated(childMetrics, true);
+  childApzc->NotifyLayersUpdated(childMetrics, true, true);
   childApzc->SampleContentTransformForFrame(&viewTransformOut, pointOut);
   EXPECT_EQ(AsyncTransform(LayerToParentLayerScale(1), ParentLayerPoint()), viewTransformOut);
   EXPECT_EQ(ParentLayerPoint(60, 60), pointOut);