diff --git a/content/base/src/nsXMLHttpRequest.cpp b/content/base/src/nsXMLHttpRequest.cpp
index 40e3c9dca96..01a99f5a759 100644
--- a/content/base/src/nsXMLHttpRequest.cpp
+++ b/content/base/src/nsXMLHttpRequest.cpp
@@ -56,7 +56,6 @@
 #include "prprf.h"
 #include "nsIDOMEventListener.h"
 #include "nsIJSContextStack.h"
-#include "nsJSEnvironment.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsWeakPtr.h"
 #include "nsICharsetAlias.h"
@@ -1777,7 +1776,6 @@ nsXMLHttpRequest::RequestCompleted()
     ChangeState(XML_HTTP_REQUEST_OPENED);
   }
 
-  nsJSContext::MaybeCC(PR_FALSE);
   return rv;
 }
 
@@ -2320,7 +2318,6 @@ nsXMLHttpRequest::Error(nsIDOMEvent* aEvent)
     NotifyEventListeners(errorEventListeners, event);
   }
 
-  nsJSContext::MaybeCC(PR_FALSE);
   return NS_OK;
 }
 
diff --git a/content/events/src/nsEventStateManager.cpp b/content/events/src/nsEventStateManager.cpp
index 83fa7a29de5..2cd1b14bcb5 100644
--- a/content/events/src/nsEventStateManager.cpp
+++ b/content/events/src/nsEventStateManager.cpp
@@ -136,9 +136,6 @@
 #include "nsEventDispatcher.h"
 #include "nsPresShellIterator.h"
 
-#include "nsServiceManagerUtils.h"
-#include "nsITimer.h"
-
 #ifdef XP_MACOSX
 #include <Events.h>
 #endif
@@ -147,8 +144,6 @@
 //#define DEBUG_DOCSHELL_FOCUS
 #endif
 
-#define NS_USER_INTERACTION_INTERVAL 5000 // ms
-
 static NS_DEFINE_CID(kFrameTraversalCID, NS_FRAMETRAVERSAL_CID);
 
 
@@ -176,41 +171,6 @@ static PRUint32 sESMInstanceCount = 0;
 static PRInt32 sChromeAccessModifier = 0, sContentAccessModifier = 0;
 PRInt32 nsEventStateManager::sUserInputEventDepth = 0;
 
-static PRUint32 gMouseOrKeyboardEventCounter = 0;
-static nsITimer* gUserInteractionTimer = nsnull;
-static nsITimerCallback* gUserInteractionTimerCallback = nsnull;
-
-class nsUITimerCallback : public nsITimerCallback
-{
-public:
-  nsUITimerCallback() : mPreviousCount(0) {}
-  NS_DECL_ISUPPORTS
-  NS_DECL_NSITIMERCALLBACK
-private:
-  PRUint32 mPreviousCount;
-};
-
-NS_IMPL_ISUPPORTS1(nsUITimerCallback, nsITimerCallback)
-
-// If aTimer is nsnull, this method always sends "user-interaction-inactive"
-// notification.
-NS_IMETHODIMP
-nsUITimerCallback::Notify(nsITimer* aTimer)
-{
-  nsresult rv;
-  nsCOMPtr<nsIObserverService> obs =
-      do_GetService("@mozilla.org/observer-service;1", &rv);
-  NS_ENSURE_SUCCESS(rv, rv);
-  if ((gMouseOrKeyboardEventCounter == mPreviousCount) || !aTimer) {
-    gMouseOrKeyboardEventCounter = 0;
-    obs->NotifyObservers(nsnull, "user-interaction-inactive", nsnull);
-  } else {
-    obs->NotifyObservers(nsnull, "user-interaction-active", nsnull);
-  }
-  mPreviousCount = gMouseOrKeyboardEventCounter;
-  return NS_OK;
-}
-
 enum {
  MOUSE_SCROLL_N_LINES,
  MOUSE_SCROLL_PAGE,
@@ -471,18 +431,6 @@ nsEventStateManager::nsEventStateManager()
     mTabbedThroughDocument(PR_FALSE),
     mAccessKeys(nsnull)
 {
-  if (sESMInstanceCount == 0) {
-    gUserInteractionTimerCallback = new nsUITimerCallback();
-    if (gUserInteractionTimerCallback) {
-      NS_ADDREF(gUserInteractionTimerCallback);
-      CallCreateInstance("@mozilla.org/timer;1", &gUserInteractionTimer);
-      if (gUserInteractionTimer) {
-        gUserInteractionTimer->InitWithCallback(gUserInteractionTimerCallback,
-                                                NS_USER_INTERACTION_INTERVAL,
-                                                nsITimer::TYPE_REPEATING_SLACK);
-      }
-    }
-  }
   ++sESMInstanceCount;
 }
 
@@ -561,14 +509,6 @@ nsEventStateManager::~nsEventStateManager()
   if(sESMInstanceCount == 0) {
     NS_IF_RELEASE(gLastFocusedContent);
     NS_IF_RELEASE(gLastFocusedDocument);
-    if (gUserInteractionTimerCallback) {
-      gUserInteractionTimerCallback->Notify(nsnull);
-      NS_RELEASE(gUserInteractionTimerCallback);
-    }
-    if (gUserInteractionTimer) {
-      gUserInteractionTimer->Cancel();
-      NS_RELEASE(gUserInteractionTimer);
-    }
   }
 
   delete mAccessKeys;
@@ -784,21 +724,6 @@ nsEventStateManager::PreHandleEvent(nsPresContext* aPresContext,
     if (!mCurrentTarget) return NS_ERROR_NULL_POINTER;
   }
 
-  if (NS_IS_TRUSTED_EVENT(aEvent) &&
-      ((aEvent->eventStructType == NS_MOUSE_EVENT  &&
-        static_cast<nsMouseEvent*>(aEvent)->reason == nsMouseEvent::eReal) ||
-       aEvent->eventStructType == NS_MOUSE_SCROLL_EVENT ||
-       aEvent->eventStructType == NS_KEY_EVENT)) {
-    if (gMouseOrKeyboardEventCounter == 0) {
-      nsCOMPtr<nsIObserverService> obs =
-        do_GetService("@mozilla.org/observer-service;1");
-      if (obs) {
-        obs->NotifyObservers(nsnull, "user-interaction-active", nsnull);
-      }
-    }
-    ++gMouseOrKeyboardEventCounter;
-  }
-
   *aStatus = nsEventStatus_eIgnore;
 
   nsMouseWheelTransaction::OnEvent(aEvent);
diff --git a/dom/src/base/nsJSEnvironment.cpp b/dom/src/base/nsJSEnvironment.cpp
index bcef36f03a9..db881ffc935 100644
--- a/dom/src/base/nsJSEnvironment.cpp
+++ b/dom/src/base/nsJSEnvironment.cpp
@@ -154,26 +154,8 @@ static PRLogModuleInfo* gJSDiagnostics;
 
 #define JAVASCRIPT nsIProgrammingLanguage::JAVASCRIPT
 
-// The max number of delayed cycle collects..
-#define NS_MAX_DELAYED_CCOLLECT     45
-// The max number of user interaction notifications in inactive state before
-// we try to call cycle collector more aggressively.
-#define NS_CC_SOFT_LIMIT_INACTIVE   6
-// The max number of user interaction notifications in active state before
-// we try to call cycle collector more aggressively.
-#define NS_CC_SOFT_LIMIT_ACTIVE     12
-// When higher probability MaybeCC is used, the number of sDelayedCCollectCount
-// is multiplied with this number.
-#define NS_PROBABILITY_MULTIPLIER   3
-// Cycle collector should never run more often than this value
-#define NS_MIN_CC_INTERVAL          5000 // ms
-
 // if you add statics here, add them to the list in nsJSRuntime::Startup
 
-static PRUint32 sDelayedCCollectCount;
-static PRUint32 sCCollectCount;
-static PRTime sPreviousCCTime;
-static PRBool sPreviousCCDidCollect;
 static nsITimer *sGCTimer;
 static PRBool sReadyForGC;
 
@@ -217,75 +199,6 @@ static nsICollation *gCollation;
 
 static nsIUnicodeDecoder *gDecoder;
 
-// nsUserActivityObserver observes user-interaction-active and
-// user-interaction-inactive notifications. It counts the number of
-// notifications and if the number is bigger than NS_CC_SOFT_LIMIT_ACTIVE
-// (in case the current notification is user-interaction-active) or
-// NS_CC_SOFT_LIMIT_INACTIVE (current notification is user-interaction-inactive)
-// MaybeCC is called with aHigherParameter set to PR_TRUE, otherwise PR_FALSE.
-//
-// When moving from active state to inactive, nsJSContext::CC() is called
-// unless the timer related to page load is active.
-
-class nsUserActivityObserver : public nsIObserver
-{
-public:
-  nsUserActivityObserver()
-  : mUserActivityCounter(0), mOldCCollectCount(0), mUserIsActive(PR_FALSE) {}
-  NS_DECL_ISUPPORTS
-  NS_DECL_NSIOBSERVER
-private:
-  PRUint32 mUserActivityCounter;
-  PRUint32 mOldCCollectCount;
-  PRBool   mUserIsActive;
-};
-
-NS_IMPL_ISUPPORTS1(nsUserActivityObserver, nsIObserver)
-
-NS_IMETHODIMP
-nsUserActivityObserver::Observe(nsISupports* aSubject, const char* aTopic,
-                                const PRUnichar* aData)
-{
-  if (mOldCCollectCount != sCCollectCount) {
-    mOldCCollectCount = sCCollectCount;
-    // Cycle collector was called between user interaction notifications, so
-    // we can reset the counter.
-    mUserActivityCounter = 0;
-  }
-  PRBool higherProbability = PR_FALSE;
-  ++mUserActivityCounter;
-  if (!strcmp(aTopic, "user-interaction-inactive")) {
-#ifdef DEBUG_smaug
-    printf("user-interaction-inactive\n");
-#endif
-    if (mUserIsActive) {
-      mUserIsActive = PR_FALSE;
-      if (!sGCTimer) {
-        nsJSContext::CC();
-        return NS_OK;
-      }
-    }
-    higherProbability = (mUserActivityCounter > NS_CC_SOFT_LIMIT_INACTIVE);
-  } else if (!strcmp(aTopic, "user-interaction-active")) {
-#ifdef DEBUG_smaug
-    printf("user-interaction-active\n");
-#endif
-    mUserIsActive = PR_TRUE;
-    higherProbability = (mUserActivityCounter > NS_CC_SOFT_LIMIT_ACTIVE);
-  } else if (!strcmp(aTopic, "xpcom-shutdown")) {
-    nsCOMPtr<nsIObserverService> obs =
-      do_GetService("@mozilla.org/observer-service;1");
-    if (obs) {
-      obs->RemoveObserver(this, "user-interaction-active");
-      obs->RemoveObserver(this, "user-interaction-inactive");
-      obs->RemoveObserver(this, "xpcom-shutdown");
-    }
-    return NS_OK;
-  }
-  nsJSContext::MaybeCC(higherProbability);
-  return NS_OK;
-}
-
 /****************************************************************
  ************************** AutoFree ****************************
  ****************************************************************/
@@ -3307,73 +3220,6 @@ nsJSContext::PreserveWrapper(nsIXPConnectWrappedNative *aWrapper)
   return nsDOMClassInfo::PreserveNodeWrapper(aWrapper);
 }
 
-//static
-void
-nsJSContext::MaybeCCOrGC(nsIScriptContext* aContext)
-{
-  if (!nsJSContext::MaybeCC(PR_TRUE)) {
-    nsCOMPtr<nsIScriptContext> context = aContext;
-    if (context) {
-      JSContext* cx = static_cast<JSContext*>(context->GetNativeContext());
-      if (cx) {
-#ifdef DEBUG_smaug
-        printf("Will call JS_GC\n");
-#endif
-        ::JS_GC(cx);
-#ifdef DEBUG_smaug
-        printf("Did call JS_GC\n");
-#endif
-      }
-    }
-  }
-}
-
-//static
-void
-nsJSContext::CC()
-{
-  sPreviousCCTime = PR_Now();
-  sDelayedCCollectCount = 0;
-  ++sCCollectCount;
-#ifdef DEBUG_smaug
-  printf("Will run cycle collector (%i)\n", sCCollectCount);
-#endif
-  // nsCycleCollector_collect() will run a ::JS_GC() indirectly, so
-  // we do not explicitly call ::JS_GC() here.
-  sPreviousCCDidCollect = nsCycleCollector_collect();
-#ifdef DEBUG_smaug
-  printf("%s\n", sPreviousCCDidCollect ?
-                   "Cycle collector did collect nodes" :
-                   "Cycle collector did not collect nodes");
-#endif
-}
-
-//static
-PRBool
-nsJSContext::MaybeCC(PRBool aHigherProbability)
-{
-  ++sDelayedCCollectCount;
-  // Increase the probability also if the previous call to cycle collector
-  // collected something.
-  if (aHigherProbability || sPreviousCCDidCollect) {
-    sDelayedCCollectCount *= NS_PROBABILITY_MULTIPLIER;
-  }
-
-  if (!sGCTimer && (sDelayedCCollectCount > NS_MAX_DELAYED_CCOLLECT)) {
-    if ((PR_Now() - sPreviousCCTime) >=
-        PRTime(NS_MIN_CC_INTERVAL * PR_USEC_PER_MSEC)) {
-      nsJSContext::CC();
-      return PR_TRUE;
-    }
-#ifdef DEBUG_smaug
-    else {
-      printf("Running cycle collector was delayed: NS_MIN_CC_INTERVAL\n");
-    }
-#endif
-  }
-  return PR_FALSE;
-}
-
 NS_IMETHODIMP
 nsJSContext::Notify(nsITimer *timer)
 {
@@ -3392,7 +3238,9 @@ nsJSContext::Notify(nsITimer *timer)
     // loading and move on as if they weren't.
     sPendingLoadCount = 0;
 
-    MaybeCCOrGC(this);
+    // nsCycleCollector_collect() will run a ::JS_GC() indirectly,
+    // so we do not explicitly call ::JS_GC() here. 
+    nsCycleCollector_collect();
   } else {
     FireGCTimer(PR_TRUE);
   }
@@ -3411,7 +3259,7 @@ nsJSContext::LoadStart()
 
 // static
 void
-nsJSContext::LoadEnd(nsIScriptGlobalObject* aGlobalObject)
+nsJSContext::LoadEnd()
 {
   // sPendingLoadCount is not a well managed load counter (and doesn't
   // need to be), so make sure we don't make it wrap backwards here.
@@ -3421,10 +3269,13 @@ nsJSContext::LoadEnd(nsIScriptGlobalObject* aGlobalObject)
 
   if (!sPendingLoadCount && sLoadInProgressGCTimer) {
     sGCTimer->Cancel();
+
     NS_RELEASE(sGCTimer);
     sLoadInProgressGCTimer = PR_FALSE;
 
-    MaybeCCOrGC(aGlobalObject ? aGlobalObject->GetContext() : nsnull);
+    // nsCycleCollector_collect() will run a ::JS_GC() indirectly, so
+    // we do not explicitly call ::JS_GC() here.
+    nsCycleCollector_collect();
   }
 }
 
@@ -3451,7 +3302,10 @@ nsJSContext::FireGCTimer(PRBool aLoadInProgress)
     // timer.
     sLoadInProgressGCTimer = PR_FALSE;
 
-    MaybeCCOrGC(this);
+    // nsCycleCollector_collect() will run a ::JS_GC() indirectly, so
+    // we do not explicitly call ::JS_GC() here.
+    nsCycleCollector_collect();
+
     return;
   }
 
@@ -3559,10 +3413,6 @@ void
 nsJSRuntime::Startup()
 {
   // initialize all our statics, so that we can restart XPCOM
-  sDelayedCCollectCount = 0;
-  sCCollectCount = 0;
-  sPreviousCCTime = 0;
-  sPreviousCCDidCollect = PR_FALSE;
   sGCTimer = nsnull;
   sReadyForGC = PR_FALSE;
   sLoadInProgressGCTimer = PR_FALSE;
@@ -3697,15 +3547,6 @@ nsJSRuntime::Init()
   MaxScriptRunTimePrefChangedCallback("dom.max_chrome_script_run_time",
                                       nsnull);
 
-  nsCOMPtr<nsIObserverService> obs =
-    do_GetService("@mozilla.org/observer-service;1", &rv);
-  NS_ENSURE_SUCCESS(rv, rv);
-  nsIObserver* activityObserver = new nsUserActivityObserver();
-  NS_ENSURE_TRUE(activityObserver, NS_ERROR_OUT_OF_MEMORY);
-  obs->AddObserver(activityObserver, "user-interaction-inactive", PR_FALSE);
-  obs->AddObserver(activityObserver, "user-interaction-active", PR_FALSE);
-  obs->AddObserver(activityObserver, "xpcom-shutdown", PR_FALSE);
-
   rv = CallGetService(NS_SCRIPTSECURITYMANAGER_CONTRACTID, &sSecurityManager);
 
   sIsInitialized = NS_SUCCEEDED(rv);
diff --git a/dom/src/base/nsJSEnvironment.h b/dom/src/base/nsJSEnvironment.h
index e074b303fe3..01d0187f8da 100644
--- a/dom/src/base/nsJSEnvironment.h
+++ b/dom/src/base/nsJSEnvironment.h
@@ -168,26 +168,7 @@ public:
   NS_DECL_NSITIMERCALLBACK
 
   static void LoadStart();
-  static void LoadEnd(nsIScriptGlobalObject* aGlobalObject);
-
-  // CC does always call cycle collector and it also updates the counters
-  // that MaybeCC uses.
-  static void CC();
-
-  // MaybeCC calls cycle collector if certain conditions are fulfilled.
-  // The conditions are:
-  // - The timer related to page load (sGCTimer) must not be active.
-  // - At least NS_MIN_CC_INTERVAL milliseconds must have elapsed since the
-  //   previous cycle collector call.
-  // - Certain number of MaybeCC calls have occurred.
-  //   The number of needed MaybeCC calls depends on the aHigherProbability
-  //   parameter. If the parameter is true, probability for calling cycle
-  //   collector rises increasingly. If the parameter is all the time false,
-  //   at least NS_MAX_DELAYED_CCOLLECT MaybeCC calls are needed.
-  //   If the previous call to cycle collector did collect something,
-  //   MaybeCC works effectively as if aHigherProbability was true.
-  // @return PR_TRUE if cycle collector was called.
-  static PRBool MaybeCC(PRBool aHigherProbability);
+  static void LoadEnd();
 
 protected:
   nsresult InitializeExternalClasses();
@@ -210,8 +191,6 @@ protected:
   nsresult JSObjectFromInterface(nsISupports *aSup, void *aScript, 
                                  JSObject **aRet);
 
-  static void MaybeCCOrGC(nsIScriptContext* aContext);
-
 private:
   JSContext *mContext;
   PRUint32 mNumEvaluations;
diff --git a/layout/base/nsDocumentViewer.cpp b/layout/base/nsDocumentViewer.cpp
index e75864fd7b9..f5d57172f30 100644
--- a/layout/base/nsDocumentViewer.cpp
+++ b/layout/base/nsDocumentViewer.cpp
@@ -993,7 +993,7 @@ DocumentViewerImpl::LoadComplete(nsresult aStatus)
     mPresShell->UnsuppressPainting();
   }
 
-  nsJSContext::LoadEnd(mDocument ? mDocument->GetScriptGlobalObject() : nsnull);
+  nsJSContext::LoadEnd();
 
 #ifdef NS_PRINTING
   // Check to see if someone tried to print during the load
diff --git a/xpcom/base/nsCycleCollector.cpp b/xpcom/base/nsCycleCollector.cpp
index b3620415037..3bfbcea446d 100644
--- a/xpcom/base/nsCycleCollector.cpp
+++ b/xpcom/base/nsCycleCollector.cpp
@@ -869,7 +869,7 @@ struct nsCycleCollector
     PRBool Forget(nsISupports *n);
     void Allocated(void *n, size_t sz);
     void Freed(void *n);
-    PRBool Collect(PRUint32 aTryCollections = 1);
+    void Collect(PRUint32 aTryCollections = 1);
     void Shutdown();
 
 #ifdef DEBUG_CC
@@ -2021,10 +2021,9 @@ nsCycleCollector::Freed(void *n)
 }
 #endif
 
-PRBool
+void
 nsCycleCollector::Collect(PRUint32 aTryCollections)
 {
-    PRBool didCollect = PR_FALSE;
 #if defined(DEBUG_CC) && !defined(__MINGW32__)
     if (!mParams.mDoNothing && mParams.mHookMalloc)
         InitMemHook();
@@ -2032,7 +2031,7 @@ nsCycleCollector::Collect(PRUint32 aTryCollections)
 
     // This can legitimately happen in a few cases. See bug 383651.
     if (mCollectionInProgress)
-        return didCollect;
+        return;
 
 #ifdef COLLECT_TIME_DEBUG
     printf("cc: Starting nsCycleCollector::Collect(%d)\n", aTryCollections);
@@ -2169,11 +2168,8 @@ nsCycleCollector::Collect(PRUint32 aTryCollections)
                 // mBuf.GetSize() == 0 check above), we should stop
                 // repeating collections if we didn't collect anything
                 // this time.
-                if (!collected) {
+                if (!collected)
                     aTryCollections = 0;
-                } else {
-                    didCollect = PR_TRUE;
-                }
             }
 
 #ifdef DEBUG_CC
@@ -2198,7 +2194,6 @@ nsCycleCollector::Collect(PRUint32 aTryCollections)
 #ifdef DEBUG_CC
     ExplainLiveExpectedGarbage();
 #endif
-    return didCollect;
 }
 
 void
@@ -2599,10 +2594,11 @@ NS_CycleCollectorForget(nsISupports *n)
 }
 
 
-PRBool
+void 
 nsCycleCollector_collect()
 {
-    return sCollector ? sCollector->Collect() : PR_FALSE;
+    if (sCollector)
+        sCollector->Collect();
 }
 
 nsresult 
diff --git a/xpcom/base/nsCycleCollector.h b/xpcom/base/nsCycleCollector.h
index ac8ceb5343e..0809ee6dfda 100644
--- a/xpcom/base/nsCycleCollector.h
+++ b/xpcom/base/nsCycleCollector.h
@@ -66,8 +66,7 @@ struct nsCycleCollectionLanguageRuntime
 NS_COM void nsCycleCollector_suspectCurrent(nsISupports *n);
 // NS_COM PRBool nsCycleCollector_forget(nsISupports *n);
 nsresult nsCycleCollector_startup();
-// Returns PR_TRUE if some nodes were collected.
-NS_COM PRBool nsCycleCollector_collect();
+NS_COM void nsCycleCollector_collect();
 void nsCycleCollector_shutdown();
 
 #ifdef DEBUG