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

- Bug 1110446 P2 Cleanup stale caches/bodies if last session didn't shutdown cleanly. r=ehsan (7925cf5fa)
- Bug 1110446 P3 Add a test that forces a Cache object to be orphaned and reclaimed. r=ehsan (c61409240)
- Bug 1110446 P4 Add a test that orphanes Cache API body files. r=ehsan (97e0a6f73)
- Bug 1157670 - Fixing an incorrect assertion in QuotaManager.cpp leads to an assertion failure; r=bent (0a19eac66)
- Bug 1165119 Remove corrupt morgue directories polluting nightly profiles. r=janv (d148170d8)
- Bug 1165119 - Follow-up to address review feedback accidentally left out of last push. r=me (f7ef96873)
- Fixup to make bug 1165119 ride the trains properly. r=trivial,DONTBUILD (87d186da4)
- Bug 1162624 - Add support for restoring corrupted or missing metadata files; r=bent (57e4341e6)
- Bug 1174113 - QuotaManager: Origin initialization fails on moz-safe-about+++home; r=bent (b7673128c)
- Bug 1142694 - QuotaManager default/temporary initialization fails on some profiles; r=bent (29a286137)
- Bug 1166871 - Always force a repaint before handling a wheel event so that we don't untransform it into some other scrollframe. r=botond (28e56646d)
- Don't vertically scroll APZCs that have less than one pixel of vertical scroll range. (bug 1154134, r=kats) (1bac9c054)
- Bug 1166871 - Add a test. r=botond (45d398bb6)
- Bug 1164557 - Do not start an overscroll animation if one is already running. r=kats (287a27910)
- Bug 1163832 - Add an API to flush pending APZ repaint requests and dispatch a notification upon completion. r=botond (8b3f9e06f)
- Bug 858680 - Part 1: Perform incremental_vacuum on open databases while idle, r=janv. (715f77ad6)
- Bug 858680 - Part 2: Add idle notifications to QuotaClient, r=janv. (9f245b1bb)
- Bug 1135166 - Initialize Telemetry histogram id cache early to avoid races. r=froydnj,vladan (f0bd8278c)
- Bug 1162176, Part 1. r=mak. (f92ba4061)
- Bug 1162176, Part 2. r=janv. (f313e1cf3)
- Bug 1155634 - Move ConnectionPool creation closer to where we actually use it and at a point guaranteed to be after QuotaManager has been started. r=khuey relanding CLOSED TREE (ce489e8f4)
- Bug 1155652 - Fix two incorrect assertions r=janv (2417d91ed)
- Bug 1156063 - Intermittent application crashed [@ mozilla::dom::indexedDB::::ConnectionPool::Start] in various tests. r=janv (b1126ac71)
- Bug 1157029 - More changes to bulletproof shutdown of failed connections, r=janv. (93a425abb)
- Bug 858680 - Part 4: Perform maintenance on databases while idle, r=janv. (017d536fe)
- Bug 1130775 - Convert synchronized ops and storage registration into unified directory locks; r=bent (300f635f7)
- Bug 1130775 followup: Add missing 'override' keyword to SendResults() methods in QuotaManager.cpp. rs=ehsan (397338f5b)
- Bug 1170021 - Part 1: Merge QuotaManager with QuotaObject; r=bent (168264350)
- Bug 1170021 - Part 2: Move DirectoryLock out of QuotaManager class; r=bent (278964f88)
- pointer style (99453953c)
- Bug 1171931 - Refactor duplicated code using XRE_IsParent/ContentProcess. r=froydnj (6d1ddbff1)

dom/base/nsDOMWindowUtils.cpp

@@ -24,6 +24,7 @@
 #include "nsIObjectLoadingContent.h"
 #include "nsFrame.h"
 #include "mozilla/layers/ShadowLayers.h"
+#include "mozilla/layers/APZCCallbackHelper.h"
 #include "ClientLayerManager.h"
 #include "nsQueryObject.h"
 #ifdef MOZ_FMP4
@@ -2487,6 +2488,34 @@ nsDOMWindowUtils::SetAsyncZoom(nsIDOMNode* aRootElement, float aValue)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDOMWindowUtils::FlushApzRepaints(bool* aOutResult)
+{
+  nsIWidget* widget = GetWidget();
+  if (!widget) {
+    *aOutResult = false;
+    return NS_OK;
+  }
+  // If APZ is not enabled, this function is a no-op.
+  if (!widget->AsyncPanZoomEnabled()) {
+    *aOutResult = false;
+    return NS_OK;
+  }
+  LayerManager* manager = widget->GetLayerManager();
+  if (!manager) {
+    *aOutResult = false;
+    return NS_OK;
+  }
+  ShadowLayerForwarder* forwarder = manager->AsShadowForwarder();
+  if (!forwarder || !forwarder->HasShadowManager()) {
+    *aOutResult = false;
+    return NS_OK;
+  }
+  forwarder->GetShadowManager()->SendFlushApzRepaints();
+  *aOutResult = true;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsDOMWindowUtils::ComputeAnimationDistance(nsIDOMElement* aElement,
                                            const nsAString& aProperty,
@@ -2949,6 +2978,24 @@ nsDOMWindowUtils::GetFileReferences(const nsAString& aDatabaseName, int64_t aId,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDOMWindowUtils::FlushPendingFileDeletions()
+{
+  MOZ_RELEASE_ASSERT(nsContentUtils::IsCallerChrome());
+
+  using mozilla::dom::indexedDB::IndexedDatabaseManager;
+
+  nsRefPtr<IndexedDatabaseManager> mgr = IndexedDatabaseManager::Get();
+  if (mgr) {
+    nsresult rv = mgr->FlushPendingFileDeletions();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+  }
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsDOMWindowUtils::IsIncrementalGCEnabled(JSContext* cx, bool* aResult)
 {