Bug 866681, part 1 - Track if any slice of CC was manually triggered. r=smaug

xpcom/base/CycleCollectedJSRuntime.h

@@ -102,6 +102,7 @@ struct CycleCollectorResults
   {
     mForcedGC = false;
     mMergedZones = false;
+    mAnyManual = false;
     mVisitedRefCounted = 0;
     mVisitedGCed = 0;
     mFreedRefCounted = 0;
@@ -114,6 +115,7 @@ struct CycleCollectorResults
 
   bool mForcedGC;
   bool mMergedZones;
+  bool mAnyManual; // true if any slice of the CC was manually triggered, or at shutdown.
   uint32_t mVisitedRefCounted;
   uint32_t mVisitedGCed;
   uint32_t mFreedRefCounted;

xpcom/base/nsCycleCollector.cpp

@@ -3594,6 +3594,10 @@ nsCycleCollector::Collect(ccType aCCType,
     timeLog.Checkpoint("Collect::FreeSnowWhite");
   }
 
+  if (aCCType != SliceCC) {
+    mResults.mAnyManual = true;
+  }
+
   ++mResults.mNumSlices;
 
   bool continueSlice = aBudget.isUnlimited() || !aPreferShorterSlices;
@@ -3779,6 +3783,7 @@ nsCycleCollector::BeginCollection(ccType aCCType,
   // Set up the data structures for building the graph.
   mGraph.Init();
   mResults.Init();
+  mResults.mAnyManual = (aCCType != SliceCC);
   bool mergeZones = ShouldMergeZones(aCCType);
   mResults.mMergedZones = mergeZones;