import changes from `dev' branch of rmottola/Arctic-Fox:

- Bug 1131308 (part 0) - Fix minor problems with RemovingIterator. r=froydnj. (5c232c9ca)
- Bug 1176163 - Remove remaining uses of PL_DHashTableEnumerate() from xpcom/. r=froydnj. (bd2478b3a)
- Bug 1179657 - Remove PL_DHASHMETER. r=froydnj. (30f581478)
- Bug 1131308 (part 1) - Improve PLDHashTable's internal checking. r=froydnj. (faba4a3b9)
- Bug 1180084 - Convert TestPLDHash.cpp to a gtest. r=froydnj. (de6ee3c5c)
- Bug 1171578 - Avoid crashing if indexedDB is used at a particular point in the worker shutdown sequence, r=baku. (f325c218e)
- Bug 804975 - Part 1: Expose WritingMode bits. r=dbaron (0635d01dd)
- Bug 1072101 - Part 1: Implement FontFaceSet.size. r=peterv (7e0b4848a)
- Bug 1144977 - Part 1: Don't include FontFace objects in more than one loadingdone/loadingerror event. r=jdaggett (4d10b3269)
- Bug 1072101 - Part 2: Implement FontFaceSet.{entries,values}. r=peterv (1c636f4f1)
- Bug 1072101 - Part 3: Implement FontFaceSet.forEach. r=peterv (842a5cdbe)
- Bug 1072101 - Part 4: Implement FontFaceSet.{keys,@@iterator}. r=peterv (4dfb3afe9)
- Bug 1072101 - Part 5: Remove indexed property access on FontFaceSet. r=peterv (edef47d70)
- Bug 1072101 - Unified build fix; no review. (7c1538f6c)
- Bug 861449 - Incremental css::Rule destroyer. r=dbaron (5e60f4394)
- Bug 1175800 - Remove typedefs from nsComputedDOMStyle.cpp as they interfere with others under unified compilation. r=bzbarsky (2bd45e7ed)
- Bug 1147766 - Part 1: Add a mozilla::RangedArray class, for fixed length arrays with a non-zero base index. r=waldo (42be428bc)
- Bug 1147766 - Part 2: Replace FixedStyleStructArray with mozilla::RangedArray. r=dbaron (4d28a0a5e)
- Bug 1171282 - Avoid some unnecessary |operator new| null-checks in layout/. r=dholbert. (60e1690c1)
- Bug 1168664 - Stop mistakenly using the transform reference box's width to calculate the Z component in ProcessMatrix3D. r=mattwoodrow (18f9021b1)
- Bug 1171842 - Use jump table instead of nested if statements for peeking compute function of style struct. r=dbaron (a5160b962)
- Bug 1170173 - Parse CSS 'contain' property. r=dholbert (3d8a37dee)
- Bug 1144607 part 1 - Remove CounterStyleManager::BuildCounterStyle for anonymous counter styles. r=dbaron (331397d01)
- Bug 1144607 part 2 - Support string value for list-style-tyle. r=dbaron (0b4bca0c7)
- Bug 1144607 part 3 - Reftests for string value on list-style-type. r=dbaron (2a483f621)
- Bug 1144607 followup - Fix submitted reftest for string value of list-style-type. DONTBUILD (ad23ac443)
- Bug 1151220 - [css-grid] Fix a couple of typos in InitializeTrackSize. r=dholbert (840f3b8a4)
- Bug 1151201 - [css-grid] Update parsing of 'auto' in track-sizing functions to latest version of the spec. r=simon.sapin (abdb0c0ea)

layout/style/IncrementalClearCOMRuleArray.cpp

@@ -0,0 +1,80 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/IncrementalClearCOMRuleArray.h"
+
+#include "nsCycleCollector.h"
+#include "mozilla/DeferredFinalize.h"
+#include "nsTArray.h"
+#include "nsCCUncollectableMarker.h"
+
+using namespace mozilla;
+
+typedef nsCOMArray<css::Rule> RuleArray;
+typedef nsTArray<RuleArray> RuleArrayArray;
+
+
+// These methods are based on those in DeferredFinalizerImpl.
+
+static void*
+AppendRulesArrayPointer(void* aData, void* aObject)
+{
+  RuleArrayArray* rulesArray = static_cast<RuleArrayArray*>(aData);
+  RuleArray* oldRules = static_cast<RuleArray*>(aObject);
+
+  if (!rulesArray) {
+    rulesArray = new RuleArrayArray();
+  }
+
+  RuleArray* newRules = rulesArray->AppendElement();
+  newRules->SwapElements(*oldRules);
+
+  return rulesArray;
+}
+
+// Remove up to |aSliceBudget| css::Rules from the arrays, starting at
+// the end of the last array.
+static bool
+DeferredFinalizeRulesArray(uint32_t aSliceBudget, void* aData)
+{
+  MOZ_ASSERT(aSliceBudget > 0, "nonsensical/useless call with aSliceBudget == 0");
+  RuleArrayArray* rulesArray = static_cast<RuleArrayArray*>(aData);
+
+  size_t newOuterLen = rulesArray->Length();
+
+  while (aSliceBudget > 0 && newOuterLen > 0) {
+    RuleArray& lastArray = rulesArray->ElementAt(newOuterLen - 1);
+    uint32_t innerLen = lastArray.Length();
+    uint32_t currSlice = std::min(innerLen, aSliceBudget);
+    uint32_t newInnerLen = innerLen - currSlice;
+    lastArray.TruncateLength(newInnerLen);
+    aSliceBudget -= currSlice;
+    if (newInnerLen == 0) {
+      newOuterLen -= 1;
+    }
+  }
+
+  rulesArray->TruncateLength(newOuterLen);
+
+  if (newOuterLen == 0) {
+    delete rulesArray;
+    return true;
+  }
+  return false;
+}
+
+void
+IncrementalClearCOMRuleArray::Clear()
+{
+  // Destroy the array incrementally if it is long and we
+  // haven't started shutting down.
+  if (Length() > 10 && nsCCUncollectableMarker::sGeneration) {
+    DeferredFinalize(AppendRulesArrayPointer, DeferredFinalizeRulesArray, this);
+  } else {
+    nsCOMArray<css::Rule>::Clear();
+  }
+  MOZ_ASSERT(Length() == 0);
+}