Bug 1307242 - Add a non-blank paint telemetry probe for foreground root content documents. r=bkelly, f=bsmedberg

This adds a probe called TIME_TO_NON_BLANK_PAINT_MS which reports time to
non-blank paint for root content documents whose docshell was active for the
entire time between navigation start and first non-blank paint.

MozReview-Commit-ID: 7JQdk5vHr1O

--HG--
extra : rebase_source : 66be2aab4c4a32d20fb44c88c5270c5b5cfc0b81
extra : histedit_source : 5d6bef86d4a2a2250405d24ce28c6bfd9d654f8d

docshell/base/nsDocShell.cpp

@@ -1728,7 +1728,9 @@ nsDocShell::MaybeInitTiming()
     mTiming = new nsDOMNavigationTiming();
   }
 
-  mTiming->NotifyNavigationStart();
+  mTiming->NotifyNavigationStart(
+    mIsActive ? nsDOMNavigationTiming::DocShellState::eActive
+              : nsDOMNavigationTiming::DocShellState::eInactive);
 }
 
 //
@@ -6219,6 +6221,20 @@ nsDocShell::SetIsActive(bool aIsActive)
     }
   }
 
+  // Tell the nsDOMNavigationTiming about it
+  RefPtr<nsDOMNavigationTiming> timing = mTiming;
+  if (!timing && mContentViewer) {
+    nsIDocument* doc = mContentViewer->GetDocument();
+    if (doc) {
+      timing = doc->GetNavigationTiming();
+    }
+  }
+  if (timing) {
+    timing->NotifyDocShellStateChanged(
+      aIsActive ? nsDOMNavigationTiming::DocShellState::eActive
+                : nsDOMNavigationTiming::DocShellState::eInactive);
+  }
+
   // Recursively tell all of our children, but don't tell <iframe mozbrowser>
   // children; they handle their state separately.
   nsTObserverArray<nsDocLoader*>::ForwardIterator iter(mChildList);

dom/base/nsDOMNavigationTiming.cpp

@@ -48,6 +48,7 @@ nsDOMNavigationTiming::Clear()
   mDOMContentLoadedEventStartSet = false;
   mDOMContentLoadedEventEndSet = false;
   mDOMCompleteSet = false;
+  mDocShellHasBeenActiveSinceNavigationStart = false;
 }
 
 DOMTimeMilliSec
@@ -66,10 +67,11 @@ DOMTimeMilliSec nsDOMNavigationTiming::DurationFromStart()
 }
 
 void
-nsDOMNavigationTiming::NotifyNavigationStart()
+nsDOMNavigationTiming::NotifyNavigationStart(DocShellState aDocShellState)
 {
   mNavigationStartHighRes = (double)PR_Now() / PR_USEC_PER_MSEC;
   mNavigationStartTimeStamp = mozilla::TimeStamp::Now();
+  mDocShellHasBeenActiveSinceNavigationStart = (aDocShellState == DocShellState::eActive);
 }
 
 void
@@ -185,7 +187,7 @@ nsDOMNavigationTiming::NotifyDOMContentLoadedEnd(nsIURI* aURI)
 }
 
 void
-nsDOMNavigationTiming::NotifyNonBlankPaint()
+nsDOMNavigationTiming::NotifyNonBlankPaintForRootContentDocument()
 {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(!mNavigationStartTimeStamp.IsNull());
@@ -202,10 +204,24 @@ nsDOMNavigationTiming::NotifyNonBlankPaint()
     if (mLoadedURI) {
       mLoadedURI->GetSpec(spec);
     }
-    nsPrintfCString marker("Non-blank paint after %dms for URL %s",
-                           int(elapsed.ToMilliseconds()), spec.get());
+    nsPrintfCString marker("Non-blank paint after %dms for URL %s, %s",
+                           int(elapsed.ToMilliseconds()), spec.get(),
+                           mDocShellHasBeenActiveSinceNavigationStart ? "foreground tab" : "this tab was inactive some of the time between navigation start and first non-blank paint");
     PROFILER_MARKER(marker.get());
   }
+
+  if (mDocShellHasBeenActiveSinceNavigationStart) {
+    Telemetry::AccumulateTimeDelta(Telemetry::TIME_TO_NON_BLANK_PAINT_MS,
+                                   mNavigationStartTimeStamp,
+                                   mNonBlankPaintTimeStamp);
+  }
+}
+
+void
+nsDOMNavigationTiming::NotifyDocShellStateChanged(DocShellState aDocShellState)
+{
+  mDocShellHasBeenActiveSinceNavigationStart &=
+    (aDocShellState == DocShellState::eActive);
 }
 
 DOMTimeMilliSec

dom/base/nsDOMNavigationTiming.h

@@ -81,7 +81,12 @@ public:
     return mLoadEventEnd;
   }
 
-  void NotifyNavigationStart();
+  enum class DocShellState : uint8_t {
+    eActive,
+    eInactive
+  };
+
+  void NotifyNavigationStart(DocShellState aDocShellState);
   void NotifyFetchStart(nsIURI* aURI, Type aNavigationType);
   void NotifyBeforeUnload();
   void NotifyUnloadAccepted(nsIURI* aOldURI);
@@ -98,7 +103,8 @@ public:
   void NotifyDOMContentLoadedStart(nsIURI* aURI);
   void NotifyDOMContentLoadedEnd(nsIURI* aURI);
 
-  void NotifyNonBlankPaint();
+  void NotifyNonBlankPaintForRootContentDocument();
+  void NotifyDocShellStateChanged(DocShellState aDocShellState);
 
   DOMTimeMilliSec TimeStampToDOM(mozilla::TimeStamp aStamp) const;
 
@@ -145,6 +151,7 @@ private:
   bool mDOMContentLoadedEventStartSet : 1;
   bool mDOMContentLoadedEventEndSet : 1;
   bool mDOMCompleteSet : 1;
+  bool mDocShellHasBeenActiveSinceNavigationStart : 1;
 };
 
 #endif /* nsDOMNavigationTiming_h___ */

image/SVGDocumentWrapper.cpp

@@ -362,7 +362,7 @@ SVGDocumentWrapper::SetupViewer(nsIRequest* aRequest,
   // automatically. Since there is no DocShell for this wrapped SVG document,
   // we must set it up manually.
   RefPtr<nsDOMNavigationTiming> timing = new nsDOMNavigationTiming();
-  timing->NotifyNavigationStart();
+  timing->NotifyNavigationStart(nsDOMNavigationTiming::DocShellState::eInactive);
   viewer->SetNavigationTiming(timing);
 
   nsCOMPtr<nsIParser> parser = do_QueryInterface(listener);

layout/base/nsPresContext.cpp

@@ -2757,9 +2757,11 @@ nsPresContext::NotifyNonBlankPaint()
 {
   MOZ_ASSERT(!mHadNonBlankPaint);
   mHadNonBlankPaint = true;
-  RefPtr<nsDOMNavigationTiming> timing = mDocument->GetNavigationTiming();
-  if (timing) {
-    timing->NotifyNonBlankPaint();
+  if (IsRootContentDocument()) {
+    RefPtr<nsDOMNavigationTiming> timing = mDocument->GetNavigationTiming();
+    if (timing) {
+      timing->NotifyNonBlankPaintForRootContentDocument();
+    }
   }
 }
 

toolkit/components/telemetry/Histograms.json

@@ -10778,5 +10778,14 @@
     "n_buckets": 50,
     "description": "Time spent painting the contents of a remote browser (ms).",
     "releaseChannelCollection": "opt-out"
+  },
+  "TIME_TO_NON_BLANK_PAINT_MS": {
+    "alert_emails": ["hkirschner@mozilla.com"],
+    "expires_in_version": "55",
+    "kind": "exponential",
+    "high": 100000,
+    "n_buckets": 100,
+    "bug_numbers": [1307242],
+    "description": "The time between navigation start and the first non-blank paint of a foreground root content document, in milliseconds. This only records documents that were in an active docshell throughout the whole time between navigation start and non-blank paint. The non-blank paint timestamp is taken during display list building and does not include rasterization or compositing of that paint."
   }
 }