Bug 681535 - XUL reflow telemetry; r=dbaron

layout/base/nsPresShell.cpp

@@ -199,6 +199,7 @@
 
 #include "mozilla/FunctionTimer.h"
 #include "mozilla/Preferences.h"
+#include "mozilla/Telemetry.h"
 
 #include "Layers.h"
 
@@ -1906,6 +1907,7 @@ PresShell::InitialReflow(nscoord aWidth, nscoord aHeight)
   }
 
   NS_TIME_FUNCTION_WITH_DOCURL;
+  mozilla::TimeStamp timerStart = mozilla::TimeStamp::Now();
 
   NS_ASSERTION(!mDidInitialReflow, "Why are we being called?");
 
@@ -2046,6 +2048,11 @@ PresShell::InitialReflow(nscoord aWidth, nscoord aHeight)
     }
   }
 
+  if (root && root->IsXUL()) {
+    mozilla::Telemetry::AccumulateTimeDelta(Telemetry::XUL_INITIAL_FRAME_CONSTRUCTION,
+                                            timerStart);
+  }
+
   return NS_OK; //XXX this needs to be real. MMP
 }
 
@@ -7331,7 +7338,7 @@ bool
 PresShell::ProcessReflowCommands(bool aInterruptible)
 {
   NS_TIME_FUNCTION_WITH_DOCURL;
-
+  mozilla::TimeStamp timerStart = mozilla::TimeStamp::Now();
   bool interrupted = false;
   if (0 != mDirtyRoots.Length()) {
 
@@ -7410,6 +7417,11 @@ PresShell::ProcessReflowCommands(bool aInterruptible)
     UnsuppressAndInvalidate();
   }
 
+  if (mDocument->GetRootElement() && mDocument->GetRootElement()->IsXUL()) {
+    mozilla::Telemetry::AccumulateTimeDelta(Telemetry::XUL_REFLOW_MS,
+                                            timerStart);
+  }
+
   return !interrupted;
 }
 

toolkit/components/telemetry/TelemetryHistograms.h

@@ -235,3 +235,5 @@ HISTOGRAM(THUNDERBIRD_INDEXING_RATE_MSG_PER_S, 1, 100, 20, LINEAR, "Gloda: index
 #endif
 
 HISTOGRAM(INNERWINDOWS_WITH_MUTATION_LISTENERS, 0, 1, 2, BOOLEAN, "Deleted or to-be-reused innerwindow which has had mutation event listeners.")
+HISTOGRAM(XUL_REFLOW_MS, 1, 3000, 10, EXPONENTIAL, "xul reflows")
+HISTOGRAM(XUL_INITIAL_FRAME_CONSTRUCTION, 1, 3000, 10, EXPONENTIAL, "initial xul frame construction")