--- a/dom/media/webspeech/recognition/SpeechRecognition.h
+++ b/dom/media/webspeech/recognition/SpeechRecognition.h
@@ -250,18 +250,18 @@ private:
   const char* GetName(SpeechEvent* aId);
 };
 
 class SpeechEvent : public Runnable
 {
 public:
   SpeechEvent(SpeechRecognition* aRecognition, SpeechRecognition::EventType aType)
   : mAudioSegment(0)
-  , mRecognitionResultList(0)
-  , mError(0)
+  , mRecognitionResultList(nullptr)
+  , mError(nullptr)
   , mRecognition(aRecognition)
   , mType(aType)
   , mTrackRate(0)
   {
   }
 
   ~SpeechEvent();
 

--- a/editor/libeditor/WSRunObject.h
+++ b/editor/libeditor/WSRunObject.h
@@ -291,17 +291,17 @@ protected:
   // stored in the struct.
   struct MOZ_STACK_CLASS WSPoint final
   {
     RefPtr<dom::Text> mTextNode;
     uint32_t mOffset;
     char16_t mChar;
 
     WSPoint()
-      : mTextNode(0)
+      : mTextNode(nullptr)
       , mOffset(0)
       , mChar(0)
     {}
 
     WSPoint(dom::Text* aTextNode, int32_t aOffset, char16_t aChar)
       : mTextNode(aTextNode)
       , mOffset(aOffset)
       , mChar(aChar)

--- a/editor/txmgr/nsTransactionList.cpp
+++ b/editor/txmgr/nsTransactionList.cpp
@@ -14,34 +14,34 @@
 #include "nsTransactionList.h"
 #include "nsTransactionStack.h"
 #include "nscore.h"
 
 NS_IMPL_ISUPPORTS(nsTransactionList, nsITransactionList)
 
 nsTransactionList::nsTransactionList(nsITransactionManager *aTxnMgr, nsTransactionStack *aTxnStack)
   : mTxnStack(aTxnStack)
-  , mTxnItem(0)
+  , mTxnItem(nullptr)
 {
   if (aTxnMgr)
     mTxnMgr = do_GetWeakReference(aTxnMgr);
 }
 
 nsTransactionList::nsTransactionList(nsITransactionManager *aTxnMgr, nsTransactionItem *aTxnItem)
   : mTxnStack(0)
   , mTxnItem(aTxnItem)
 {
   if (aTxnMgr)
     mTxnMgr = do_GetWeakReference(aTxnMgr);
 }
 
 nsTransactionList::~nsTransactionList()
 {
   mTxnStack = 0;
-  mTxnItem  = 0;
+  mTxnItem  = nullptr;
 }
 
 NS_IMETHODIMP nsTransactionList::GetNumItems(int32_t *aNumItems)
 {
   NS_ENSURE_TRUE(aNumItems, NS_ERROR_NULL_POINTER);
 
   *aNumItems = 0;
 

--- a/ipc/chromium/src/base/object_watcher.cc
+++ b/ipc/chromium/src/base/object_watcher.cc
@@ -33,17 +33,17 @@ public:
     delegate->OnObjectSignaled(object);
 
     return NS_OK;
   }
 };
 
 //-----------------------------------------------------------------------------
 
-ObjectWatcher::ObjectWatcher() : watch_(NULL) {
+ObjectWatcher::ObjectWatcher() : watch_(nullptr) {
 }
 
 ObjectWatcher::~ObjectWatcher() {
   StopWatching();
 }
 
 bool ObjectWatcher::StartWatching(HANDLE object, Delegate* delegate) {
   if (watch_) {
@@ -94,17 +94,17 @@ bool ObjectWatcher::StopWatching() {
   // since we expect that UnregisterWaitEx resulted in a memory barrier, but
   // just to be sure, we're going to be explicit.
   MemoryBarrier();
 
   // If the watch has been posted, then we need to make sure it knows not to do
   // anything once it is run.
   watch_->watcher = NULL;
 
-  watch_ = NULL;
+  watch_ = nullptr;
 
   MessageLoop::current()->RemoveDestructionObserver(this);
   return true;
 }
 
 HANDLE ObjectWatcher::GetWatchedObject() {
   if (!watch_)
     return NULL;

--- a/ipc/chromium/src/base/timer.cc
+++ b/ipc/chromium/src/base/timer.cc
@@ -7,18 +7,18 @@
 #include "base/timer.h"
 
 #include "base/message_loop.h"
 
 namespace base {
 
 void BaseTimer_Helper::OrphanDelayedTask() {
   if (delayed_task_) {
-    delayed_task_->timer_ = NULL;
-    delayed_task_ = NULL;
+    delayed_task_->timer_ = nullptr;
+    delayed_task_ = nullptr;
   }
 }
 
 void BaseTimer_Helper::InitiateDelayedTask(TimerTask* timer_task) {
   OrphanDelayedTask();
 
   delayed_task_ = timer_task;
   delayed_task_->timer_ = this;

--- a/ipc/chromium/src/base/timer.h
+++ b/ipc/chromium/src/base/timer.h
@@ -171,17 +171,17 @@ class BaseTimer : public BaseTimer_Helpe
     // Inform the Base that the timer is no longer active.
     void ClearBaseTimer() {
       if (timer_) {
         SelfType* self = static_cast<SelfType*>(timer_);
         // It is possible that the Timer has already been reset, and that this
         // Task is old.  So, if the Timer points to a different task, assume
         // that the Timer has already taken care of properly setting the task.
         if (self->delayed_task_ == this)
-          self->delayed_task_ = NULL;
+          self->delayed_task_ = nullptr;
         // By now the delayed_task_ in the Timer does not point to us anymore.
         // We should reset our own timer_ because the Timer can not do this
         // for us in its destructor.
         timer_ = NULL;
       }
     }
 
     // Inform the Base that we're resetting the timer.

--- a/netwerk/cache/nsDiskCacheDeviceSQL.cpp
+++ b/netwerk/cache/nsDiskCacheDeviceSQL.cpp
@@ -1408,17 +1408,17 @@ nsOfflineCacheDevice::Shutdown()
     "  (SELECT moz_cache_namespaces.rowid FROM"
     "    moz_cache_namespaces LEFT OUTER JOIN moz_cache_groups ON"
     "      (moz_cache_namespaces.ClientID = moz_cache_groups.ActiveClientID)"
     "   WHERE moz_cache_groups.GroupID ISNULL)"));
 
   if (NS_FAILED(rv))
     NS_WARNING("Failed to clean up namespaces.");
 
-  mEvictionFunction = 0;
+  mEvictionFunction = nullptr;
 
   mStatement_CacheSize = nullptr;
   mStatement_ApplicationCacheSize = nullptr;
   mStatement_EntryCount = nullptr;
   mStatement_UpdateEntry = nullptr;
   mStatement_UpdateEntrySize = nullptr;
   mStatement_DeleteEntry = nullptr;
   mStatement_FindEntry = nullptr;

--- a/netwerk/protocol/http/HttpChannelParent.cpp
+++ b/netwerk/protocol/http/HttpChannelParent.cpp
@@ -782,17 +782,17 @@ HttpChannelParent::RecvRedirect2Verify(c
 
   return true;
 }
 
 bool
 HttpChannelParent::RecvDocumentChannelCleanup()
 {
   // From now on only using mAssociatedContentSecurity.  Free everything else.
-  mChannel = 0;          // Reclaim some memory sooner.
+  mChannel = nullptr;          // Reclaim some memory sooner.
   mCacheEntry = 0;  // Else we'll block other channels reading same URI
   return true;
 }
 
 bool
 HttpChannelParent::RecvMarkOfflineCacheEntryAsForeign()
 {
   if (mOfflineForeignMarker) {

--- a/netwerk/streamconv/converters/nsMultiMixedConv.cpp
+++ b/netwerk/streamconv/converters/nsMultiMixedConv.cpp
@@ -908,17 +908,17 @@ nsMultiMixedConv::SendStop(nsresult aSta
 
         // Remove the channel from its load group (if any)
         nsCOMPtr<nsILoadGroup> loadGroup;
         (void) mPartChannel->GetLoadGroup(getter_AddRefs(loadGroup));
         if (loadGroup) 
             (void) loadGroup->RemoveRequest(mPartChannel, mContext, aStatus);
     }
 
-    mPartChannel = 0;
+    mPartChannel = nullptr;
     return rv;
 }
 
 nsresult
 nsMultiMixedConv::SendData(char *aBuffer, uint32_t aLen) {
 
     nsresult rv = NS_OK;
     

--- a/toolkit/components/places/tests/cpp/mock_Link.h
+++ b/toolkit/components/places/tests/cpp/mock_Link.h
@@ -35,17 +35,17 @@ public:
   }
 
   virtual void SetLinkState(nsLinkState aState) override
   {
     // Notify our callback function.
     mHandler(aState);
 
     // Break the cycle so the object can be destroyed.
-    mDeathGrip = 0;
+    mDeathGrip = nullptr;
   }
 
   virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const override
   {
     return 0;   // the value shouldn't matter
   }
 
 protected: