Bug 1141614 - Part 1: Maintain a list of docshells whose timeline markers are being observed; r=smaug

docshell/base/nsDocShell.cpp

@@ -944,7 +944,7 @@ nsDocShell::nsDocShell()
 
 nsDocShell::~nsDocShell()
 {
-  MOZ_ASSERT(!mProfileTimelineRecording);
+  MOZ_ASSERT(!IsObserved());
 
   Destroy();
 
@@ -2927,6 +2927,8 @@ nsDocShell::HistoryTransactionRemoved(int32_t aIndex)
 
 unsigned long nsDocShell::gProfileTimelineRecordingsCount = 0;
 
+mozilla::LinkedList<nsDocShell::ObservedDocShell>* nsDocShell::gObservedDocShells = nullptr;
+
 NS_IMETHODIMP
 nsDocShell::SetRecordProfileTimelineMarkers(bool aValue)
 {
@@ -2935,11 +2937,16 @@ nsDocShell::SetRecordProfileTimelineMarkers(bool aValue)
     if (aValue) {
       ++gProfileTimelineRecordingsCount;
       UseEntryScriptProfiling();
-      mProfileTimelineRecording = true;
+
+      MOZ_ASSERT(!mObserved);
+      mObserved.reset(new ObservedDocShell(this));
+      GetOrCreateObservedDocShells().insertFront(mObserved.get());
     } else {
       --gProfileTimelineRecordingsCount;
       UnuseEntryScriptProfiling();
-      mProfileTimelineRecording = false;
+
+      mObserved.reset(nullptr);
+
       ClearProfileTimelineMarkers();
     }
   }
@@ -2950,7 +2957,7 @@ nsDocShell::SetRecordProfileTimelineMarkers(bool aValue)
 NS_IMETHODIMP
 nsDocShell::GetRecordProfileTimelineMarkers(bool* aValue)
 {
-  *aValue = mProfileTimelineRecording;
+  *aValue = IsObserved();
   return NS_OK;
 }
 
@@ -3090,7 +3097,7 @@ void
 nsDocShell::AddProfileTimelineMarker(const char* aName,
                                      TracingMetadata aMetaData)
 {
-  if (mProfileTimelineRecording) {
+  if (IsObserved()) {
     TimelineMarker* marker = new TimelineMarker(this, aName, aMetaData);
     mProfileTimelineMarkers.AppendElement(marker);
   }
@@ -3099,7 +3106,7 @@ nsDocShell::AddProfileTimelineMarker(const char* aName,
 void
 nsDocShell::AddProfileTimelineMarker(UniquePtr<TimelineMarker>&& aMarker)
 {
-  if (mProfileTimelineRecording) {
+  if (IsObserved()) {
     mProfileTimelineMarkers.AppendElement(Move(aMarker));
   }
 }

docshell/base/nsDocShell.h

@@ -23,6 +23,7 @@
 #include "mozilla/TimeStamp.h"
 #include "GeckoProfiler.h"
 #include "mozilla/dom/ProfileTimelineMarkerBinding.h"
+#include "mozilla/LinkedList.h"
 #include "jsapi.h"
 
 // Helper Classes
@@ -266,6 +267,43 @@ public:
   // timeline markers
   static unsigned long gProfileTimelineRecordingsCount;
 
+  class ObservedDocShell : public mozilla::LinkedListElement<ObservedDocShell>
+  {
+  public:
+    explicit ObservedDocShell(nsDocShell* aDocShell)
+      : mDocShell(aDocShell)
+    { }
+
+    nsDocShell* operator*() const { return mDocShell.get(); }
+
+  private:
+    nsRefPtr<nsDocShell> mDocShell;
+  };
+
+private:
+  static mozilla::LinkedList<ObservedDocShell>* gObservedDocShells;
+
+  static mozilla::LinkedList<ObservedDocShell>& GetOrCreateObservedDocShells()
+  {
+    if (!gObservedDocShells) {
+      gObservedDocShells = new mozilla::LinkedList<ObservedDocShell>();
+    }
+    return *gObservedDocShells;
+  }
+
+  // Never null if timeline markers are being observed.
+  mozilla::UniquePtr<ObservedDocShell> mObserved;
+
+  // Return true if timeline markers are being observed for this docshell. False
+  // otherwise.
+  bool IsObserved() const { return !!mObserved; }
+
+public:
+  static const mozilla::LinkedList<ObservedDocShell>& GetObservedDocShells()
+  {
+    return GetOrCreateObservedDocShells();
+  }
+
   // Tell the favicon service that aNewURI has the same favicon as aOldURI.
   static void CopyFavicon(nsIURI* aOldURI,
                           nsIURI* aNewURI,
@@ -973,9 +1011,6 @@ private:
   // has been called without a matching NotifyRunToCompletionStop.
   uint32_t mJSRunToCompletionDepth;
 
-  // True if recording profiles.
-  bool mProfileTimelineRecording;
-
   nsTArray<mozilla::UniquePtr<TimelineMarker>> mProfileTimelineMarkers;
 
   // Get rid of all the timeline markers accumulated so far