--- a/client.mk
+++ b/client.mk
@@ -209,19 +209,19 @@ everything: clean build
 #  application until all the build passes and postflight scripts have run.
 ifdef MOZ_OBJDIR
   PGO_OBJDIR = $(MOZ_OBJDIR)
 else
   PGO_OBJDIR := $(TOPSRCDIR)
 endif
 
 profiledbuild::
-	$(MAKE) -f $(TOPSRCDIR)/client.mk realbuild MOZ_PROFILE_GENERATE=1 MOZ_PGO_INSTRUMENTED=1
-	$(MAKE) -C $(PGO_OBJDIR) stage-package MOZ_PGO_INSTRUMENTED=1
-	MOZ_PGO_INSTRUMENTED=1 OBJDIR=${PGO_OBJDIR} JARLOG_DIR=${PGO_OBJDIR}/jarlog/en-US $(PROFILE_GEN_SCRIPT)
+	$(MAKE) -f $(TOPSRCDIR)/client.mk realbuild MOZ_PROFILE_GENERATE=1
+	$(MAKE) -C $(PGO_OBJDIR) stage-package
+	OBJDIR=${PGO_OBJDIR} JARLOG_DIR=${PGO_OBJDIR}/jarlog/en-US $(PROFILE_GEN_SCRIPT)
 	$(MAKE) -f $(TOPSRCDIR)/client.mk maybe_clobber_profiledbuild
 	$(MAKE) -f $(TOPSRCDIR)/client.mk realbuild MOZ_PROFILE_USE=1
 
 #####################################################
 # Build date unification
 
 ifdef MOZ_UNIFY_BDATE
 ifndef MOZ_BUILD_DATE

--- a/modules/libpref/src/init/all.js
+++ b/modules/libpref/src/init/all.js
@@ -3404,22 +3404,8 @@ pref("dom.sms.whitelist", "");
 // enable JS dump() function.
 pref("browser.dom.window.dump.enabled", false);
 
 // SPS Profiler
 pref("profiler.enabled", false);
 pref("profiler.interval", 10);
 pref("profiler.entries", 100000);
 
-#ifdef XP_WIN
-// On 32-bit Windows, fire a low-memory notification if we have less than this
-// many mb of virtual address space available.
-pref("memory.low_virtual_memory_threshold_mb", 128);
-
-// On Windows 32- or 64-bit, fire a low-memory notification if we have less
-// than this many mb of physical memory available on the whole machine.
-pref("memory.low_physical_mem_threshold_mb", 0);
-
-// On Windows 32- or 64-bit, don't fire a low-memory notification because of
-// low available physical memory more than once every
-// low_physical_memory_notification_interval_ms.
-pref("memory.low_physical_memory_notification_interval_ms", 10000);
-#endif

deleted file mode 100644
--- a/xpcom/base/AvailableMemoryTracker.cpp
+++ /dev/null
@@ -1,333 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim:set ts=2 sw=2 sts=2 ci et: */
-/* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla.org code.
- *
- * The Initial Developer of the Original Code is
- * the Mozilla Foundation.
- * Portions created by the Initial Developer are Copyright (C) 2011
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *   Justin Lebar <justin.lebar@gmail.com>
- *
- * ***** END LICENSE BLOCK ***** */
-
-#include "mozilla/AvailableMemoryTracker.h"
-#include "nsThread.h"
-#include "nsIObserverService.h"
-#include "mozilla/Services.h"
-#include "mozilla/Preferences.h"
-#include "nsWindowsDllInterceptor.h"
-#include "prinrval.h"
-#include "pratom.h"
-#include "prenv.h"
-#include <windows.h>
-
-namespace mozilla {
-namespace AvailableMemoryTracker {
-
-// We don't want our diagnostic functions to call malloc, because that could
-// call VirtualAlloc, and we'd end up back in here!  So here are a few simple
-// debugging macros (modeled on jemalloc's), which hopefully won't allocate.
-
-// #define LOGGING_ENABLED
-
-#ifdef LOGGING_ENABLED
-
-#define LOG(msg)       \
-  do {                 \
-    safe_write(msg);   \
-    safe_write("\n");  \
-  } while(0)
-
-#define LOG2(m1, m2)   \
-  do {                 \
-    safe_write(m1);    \
-    safe_write(m2);    \
-    safe_write("\n");  \
-  } while(0)
-
-#define LOG3(m1, m2, m3) \
-  do {                   \
-    safe_write(m1);      \
-    safe_write(m2);      \
-    safe_write(m3);      \
-    safe_write("\n");    \
-  } while(0)
-
-#define LOG4(m1, m2, m3, m4) \
-  do {                       \
-    safe_write(m1);          \
-    safe_write(m2);          \
-    safe_write(m3);          \
-    safe_write(m4);          \
-    safe_write("\n");        \
-  } while(0)
-
-#else
-
-#define LOG(msg)
-#define LOG2(m1, m2)
-#define LOG3(m1, m2, m3)
-#define LOG4(m1, m2, m3, m4)
-
-#endif
-
-void safe_write(const char *a)
-{
-  // Well, puts isn't exactly "safe", but at least it doesn't call malloc...
-  fputs(a, stdout);
-}
-
-void safe_write(PRUint64 x)
-{
-  // 2^64 is 20 decimal digits.
-  const int max_len = 21;
-  char buf[max_len];
-  buf[max_len - 1] = '\0';
-
-  PRUint32 i;
-  for (i = max_len - 2; i >= 0 && x > 0; i--)
-  {
-    buf[i] = "0123456789"[x % 10];
-    x /= 10;
-  }
-
-  safe_write(&buf[i + 1]);
-}
-
-#ifdef DEBUG
-#define DEBUG_WARN_IF_FALSE(cond, msg)          \
-  do {                                          \
-    if (!(cond)) {                              \
-      safe_write(__FILE__);                     \
-      safe_write(":");                          \
-      safe_write(__LINE__);                     \
-      safe_write(" ");                          \
-      safe_write(msg);                          \
-      safe_write("\n");                         \
-    }                                           \
-  } while(0)
-#else
-#define DEBUG_WARN_IF_FALSE(cond, msg)
-#endif
-
-PRUint32 sLowVirtualMemoryThreshold = 0;
-PRUint32 sLowPhysicalMemoryThreshold = 0;
-PRUint32 sLowPhysicalMemoryNotificationIntervalMS = 0;
-
-WindowsDllInterceptor sKernel32Intercept;
-WindowsDllInterceptor sGdi32Intercept;
-
-// Alas, we'd like to use mozilla::TimeStamp, but we can't, because it acquires
-// a lock!
-volatile bool sHasScheduledOneLowMemoryNotification = false;
-volatile PRIntervalTime sLastLowMemoryNotificationTime;
-
-// These are function pointers to the functions we wrap in Init().
-
-void* (WINAPI *sVirtualAllocOrig)
-  (LPVOID aAddress, SIZE_T aSize, DWORD aAllocationType, DWORD aProtect);
-
-void* (WINAPI *sMapViewOfFileOrig)
-  (HANDLE aFileMappingObject, DWORD aDesiredAccess,
-   DWORD aFileOffsetHigh, DWORD aFileOffsetLow,
-   SIZE_T aNumBytesToMap);
-
-HBITMAP (WINAPI *sCreateDIBSectionOrig)
-  (HDC aDC, const BITMAPINFO *aBitmapInfo,
-   UINT aUsage, VOID **aBits,
-   HANDLE aSection, DWORD aOffset);
-
-void CheckMemAvailable()
-{
-  MEMORYSTATUSEX stat;
-  stat.dwLength = sizeof(stat);
-  bool success = GlobalMemoryStatusEx(&stat);
-
-  DEBUG_WARN_IF_FALSE(success, "GlobalMemoryStatusEx failed.");
-
-  if (success)
-  {
-    // sLowVirtualMemoryThreshold is in MB, but ullAvailVirtual is in bytes.
-    if (stat.ullAvailVirtual < sLowVirtualMemoryThreshold * 1024 * 1024) {
-      // If we're running low on virtual memory, schedule the notification.
-      // We'll probably crash if we run out of virtual memory, so don't worry
-      // about firing this notification too often.
-      LOG("Detected low virtual memory.");
-      ScheduleMemoryPressureEvent();
-    }
-    else if (stat.ullAvailPhys < sLowPhysicalMemoryThreshold * 1024 * 1024) {
-      LOG("Detected low physical memory.");
-      // If the machine is running low on physical memory and it's been long
-      // enough since we last fired a low-memory notification, fire a
-      // notification.
-      //
-      // If this interval rolls over, we may fire an extra memory pressure
-      // event, but that's not a big deal.
-      PRIntervalTime interval = PR_IntervalNow() - sLastLowMemoryNotificationTime;
-      if (!sHasScheduledOneLowMemoryNotification ||
-          PR_IntervalToMilliseconds(interval) >=
-            sLowPhysicalMemoryNotificationIntervalMS) {
-
-        // There's a bit of a race condition here, since an interval may be a
-        // 64-bit number, and 64-bit writes aren't atomic on x86-32.  But let's
-        // not worry about it -- the races only happen when we're already
-        // experiencing memory pressure and firing notifications, so the worst
-        // thing that can happen is that we fire two notifications when we
-        // should have fired only one.
-        sHasScheduledOneLowMemoryNotification = true;
-        sLastLowMemoryNotificationTime = PR_IntervalNow();
-
-        LOG("Scheduling memory pressure notification.");
-        ScheduleMemoryPressureEvent();
-      }
-      else {
-        LOG("Not scheduling low physical memory notification, "
-            "because not enough time has elapsed since last one.");
-      }
-    }
-  }
-}
-
-LPVOID WINAPI
-VirtualAllocHook(LPVOID aAddress, SIZE_T aSize,
-                 DWORD aAllocationType,
-                 DWORD aProtect)
-{
-  // It's tempting to see whether we have enough free virtual address space for
-  // this allocation and, if we don't, synchronously fire a low-memory
-  // notification to free some before we allocate.
-  //
-  // Unfortunately that doesn't work, principally because code doesn't expect a
-  // call to malloc could trigger a GC (or call into the other routines which
-  // are triggered by a low-memory notification).
-  //
-  // I think the best we can do here is try to allocate the memory and check
-  // afterwards how much free virtual address space we have.  If we're running
-  // low, we schedule a low-memory notification to run as soon as possible.
-
-  LPVOID result = sVirtualAllocOrig(aAddress, aSize, aAllocationType, aProtect);
-
-  // Don't call CheckMemAvailable for MEM_RESERVE if we're not tracking low
-  // virtual memory.  Similarly, don't call CheckMemAvailable for MEM_COMMIT if
-  // we're not tracking low physical memory.
-  if ((sLowVirtualMemoryThreshold != 0 && aAllocationType & MEM_RESERVE) ||
-      (sLowPhysicalMemoryThreshold != 0 &&  aAllocationType & MEM_COMMIT)) {
-    LOG3("VirtualAllocHook(size=", aSize, ")");
-    CheckMemAvailable();
-  }
-
-  return result;
-}
-
-LPVOID WINAPI
-MapViewOfFileHook(HANDLE aFileMappingObject,
-                  DWORD aDesiredAccess,
-                  DWORD aFileOffsetHigh,
-                  DWORD aFileOffsetLow,
-                  SIZE_T aNumBytesToMap)
-{
-  LPVOID result = sMapViewOfFileOrig(aFileMappingObject, aDesiredAccess,
-                                     aFileOffsetHigh, aFileOffsetLow,
-                                     aNumBytesToMap);
-  LOG("MapViewOfFileHook");
-  CheckMemAvailable();
-  return result;
-}
-
-HBITMAP WINAPI
-CreateDIBSectionHook(HDC aDC,
-                     const BITMAPINFO *aBitmapInfo,
-                     UINT aUsage,
-                     VOID **aBits,
-                     HANDLE aSection,
-                     DWORD aOffset)
-{
-  // There are a lot of calls to CreateDIBSection, so we make some effort not
-  // to CheckMemAvailable() for calls to CreateDIBSection which allocate only
-  // a small amount of memory.
-
-  // If aSection is non-null, CreateDIBSection won't allocate any new memory.
-  PRBool doCheck = PR_FALSE;
-  if (!aSection && aBitmapInfo) {
-    PRUint16 bitCount = aBitmapInfo->bmiHeader.biBitCount;
-    if (bitCount == 0) {
-      // MSDN says bitCount == 0 means that it figures out how many bits each
-      // pixel gets by examining the corresponding JPEG or PNG data.  We'll just
-      // assume the worst.
-      bitCount = 32;
-    }
-
-    // |size| contains the expected allocation size in *bits*.  Height may be
-    // negative (indicating the direction the DIB is drawn in), so we take the
-    // absolute value.
-    PRInt64 size = bitCount * aBitmapInfo->bmiHeader.biWidth *
-                              aBitmapInfo->bmiHeader.biHeight;
-    if (size < 0)
-      size *= -1;
-
-    // If we're allocating more than 1MB, check how much virtual memory is left
-    // after the allocation.
-    if (size > 1024 * 1024 * 8) {
-      LOG3("CreateDIBSectionHook: Large allocation (size=", size, ")");
-      doCheck = PR_TRUE;
-    }
-  }
-
-  HBITMAP result = sCreateDIBSectionOrig(aDC, aBitmapInfo, aUsage, aBits,
-                                         aSection, aOffset);
-
-  if (doCheck) {
-    CheckMemAvailable();
-  }
-
-  return result;
-}
-
-void Init()
-{
-  Preferences::AddUintVarCache(&sLowVirtualMemoryThreshold,
-      "memory.low_virtual_mem_threshold_mb", 128);
-  Preferences::AddUintVarCache(&sLowPhysicalMemoryThreshold,
-      "memory.low_physical_mem_threshold_mb", 0);
-  Preferences::AddUintVarCache(&sLowPhysicalMemoryNotificationIntervalMS,
-      "memory.low_physical_memory_notification_interval_ms", 10000);
-
-  // Don't register the hooks if we're a build instrumented for PGO or if both
-  // thresholds are 0.  (If we're an instrumented build, the compiler adds
-  // function calls all over the place which may call VirtualAlloc; this makes
-  // it hard to prevent VirtualAllocHook from reentering itself.)
-
-  if (!PR_GetEnv("MOZ_PGO_INSTRUMENTED") &&
-      (sLowVirtualMemoryThreshold != 0 || sLowPhysicalMemoryThreshold != 0)) {
-    sKernel32Intercept.Init("Kernel32.dll");
-    sKernel32Intercept.AddHook("VirtualAlloc",
-      reinterpret_cast<intptr_t>(VirtualAllocHook),
-      (void**) &sVirtualAllocOrig);
-    sKernel32Intercept.AddHook("MapViewOfFile",
-      reinterpret_cast<intptr_t>(MapViewOfFileHook),
-      (void**) &sMapViewOfFileOrig);
-
-    sGdi32Intercept.Init("Gdi32.dll");
-    sGdi32Intercept.AddHook("CreateDIBSection",
-      reinterpret_cast<intptr_t>(CreateDIBSectionHook),
-      (void**) &sCreateDIBSectionOrig);
-  }
-}
-
-} // namespace AvailableMemoryTracker
-} // namespace mozilla

deleted file mode 100644
--- a/xpcom/base/AvailableMemoryTracker.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim:set ts=2 sw=2 sts=2 ci et: */
-/* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla.org code.
- *
- * The Initial Developer of the Original Code is
- * the Mozilla Foundation.
- * Portions created by the Initial Developer are Copyright (C) 2011
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *   Justin Lebar <justin.lebar@gmail.com>
- *
- * ***** END LICENSE BLOCK ***** */
-
-#ifndef mozilla_AvailableMemoryTracker_h
-#define mozilla_AvailableMemoryTracker_h
-
-namespace mozilla {
-namespace AvailableMemoryTracker {
-
-// The AvailableMemoryTracker is implemented only on Windows.  But to make
-// callers' lives easier, we stub out an empty Init() call.  So you can always
-// initialize the AvailableMemoryTracker; it just might not do anything.
-
-#if defined(XP_WIN)
-void Init();
-#else
-void Init() {}
-#endif
-
-} // namespace AvailableMemoryTracker
-} // namespace mozilla
-
-#endif // ifndef mozilla_AvailableMemoryTracker_h

--- a/xpcom/base/Makefile.in
+++ b/xpcom/base/Makefile.in
@@ -95,36 +95,29 @@ EXPORTS		= \
 		dmd.h \
 		$(NULL)
 
 EXPORTS_NAMESPACES = mozilla
 
 EXPORTS_mozilla = \
 	FunctionTimer.h \
 	MapsMemoryReporter.h \
-	AvailableMemoryTracker.h \
 	$(NULL)
 
 ifeq (windows,$(MOZ_WIDGET_TOOLKIT))
 CPPSRCS += nsCrashOnException.cpp
 endif
 
 ifeq ($(OS_ARCH),WINNT)
-
 ifdef MOZ_DEBUG
 CSRCS		+= pure_api.c
 EXPORTS		+= pure.h
 endif
-
-ifeq ($(CPU_ARCH),x86)
-CPPSRCS += AvailableMemoryTracker.cpp
 endif
 
-endif #if OS_ARCH == WINNT
-
 SDK_XPIDLSRCS   = \
 		nsIDebug.idl               \
 		nsIInterfaceRequestor.idl  \
 		nsIMemory.idl		   \
 		nsIProgrammingLanguage.idl \
 		nsISupports.idl		   \
 		nsITraceRefcnt.idl         \
 		nsIWeakReference.idl	   \

--- a/xpcom/build/nsXPComInit.cpp
+++ b/xpcom/build/nsXPComInit.cpp
@@ -147,17 +147,16 @@ extern nsresult nsStringInputStreamConst
 #include "mozilla/scache/StartupCache.h"
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/message_loop.h"
 
 #include "mozilla/ipc/BrowserProcessSubThread.h"
 #include "mozilla/MapsMemoryReporter.h"
-#include "mozilla/AvailableMemoryTracker.h"
 
 using base::AtExitManager;
 using mozilla::ipc::BrowserProcessSubThread;
 
 namespace {
 
 static AtExitManager* sExitManager;
 static MessageLoop* sMessageLoop;
@@ -515,18 +514,16 @@ NS_InitXPCOM2(nsIServiceManager* *result
     NS_TIME_FUNCTION_MARK("Next: register category providers");
 
     // After autoreg, but before we actually instantiate any components,
     // add any services listed in the "xpcom-directory-providers" category
     // to the directory service.
     nsDirectoryService::gService->RegisterCategoryProviders();
 
     mozilla::scache::StartupCache::GetSingleton();
-    mozilla::AvailableMemoryTracker::Init();
-
     NS_TIME_FUNCTION_MARK("Next: create services from category");
 
     // Notify observers of xpcom autoregistration start
     NS_CreateServicesFromCategory(NS_XPCOM_STARTUP_CATEGORY, 
                                   nsnull,
                                   NS_XPCOM_STARTUP_OBSERVER_ID);
 #ifdef XP_WIN
     ScheduleMediaCacheRemover();

--- a/xpcom/threads/Makefile.in
+++ b/xpcom/threads/Makefile.in
@@ -59,17 +59,16 @@ CPPSRCS		= \
 		nsThreadPool.cpp \
 		nsProcessCommon.cpp \
 		nsTimerImpl.cpp \
 		TimerThread.cpp \
 		HangMonitor.cpp \
 		$(NULL)
 
 EXPORTS		= \
-		nsThread.h \
 		nsProcess.h \
 		nsEventQueue.h \
 		nsThreadUtilsInternal.h \
 		$(NULL)
 
 EXPORTS_mozilla = \
   HangMonitor.h \
   $(NULL)

--- a/xpcom/threads/nsThread.cpp
+++ b/xpcom/threads/nsThread.cpp
@@ -40,19 +40,17 @@
 #include "nsThread.h"
 #include "nsThreadManager.h"
 #include "nsIClassInfoImpl.h"
 #include "nsIProgrammingLanguage.h"
 #include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "prlog.h"
 #include "nsThreadUtilsInternal.h"
-#include "nsIObserverService.h"
 #include "mozilla/HangMonitor.h"
-#include "mozilla/Services.h"
 
 #define HAVE_UALARM _BSD_SOURCE || (_XOPEN_SOURCE >= 500 ||                 \
                       _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) &&           \
                       !(_POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700)
 
 #if defined(XP_UNIX) && !defined(ANDROID) && !defined(DEBUG) && HAVE_UALARM \
   && defined(_GNU_SOURCE)
 # define MOZ_CANARY
@@ -78,31 +76,16 @@ using namespace mozilla;
 static PRLogModuleInfo *sLog = PR_NewLogModule("nsThread");
 #endif
 #define LOG(args) PR_LOG(sLog, PR_LOG_DEBUG, args)
 
 NS_DECL_CI_INTERFACE_GETTER(nsThread)
 
 nsIThreadObserver* nsThread::sGlobalObserver;
 
-namespace mozilla {
-
-static volatile bool sMemoryPressurePending = false;
-
-/*
- * It's important that this function not acquire any locks, nor do anything
- * which might cause malloc to run.
- */
-void ScheduleMemoryPressureEvent()
-{
-  PR_ATOMIC_SET(&sMemoryPressurePending, true);
-}
-
-};
-
 //-----------------------------------------------------------------------------
 // Because we do not have our own nsIFactory, we have to implement nsIClassInfo
 // somewhat manually.
 
 class nsThreadClassInfo : public nsIClassInfo {
 public:
   NS_DECL_ISUPPORTS_INHERITED  // no mRefCnt
   NS_DECL_NSICLASSINFO
@@ -589,32 +572,16 @@ nsThread::ProcessNextEvent(bool mayWait,
 {
   LOG(("THRD(%p) ProcessNextEvent [%u %u]\n", this, mayWait, mRunningEvent));
 
   NS_ENSURE_STATE(PR_GetCurrentThread() == mThread);
 
   if (MAIN_THREAD == mIsMainThread && mayWait && !ShuttingDown())
     HangMonitor::Suspend();
 
-  // Fire a memory pressure notification, if we're the main thread and one is
-  // pending.
-  if (MAIN_THREAD == mIsMainThread && !ShuttingDown()) {
-    bool mpPending = PR_ATOMIC_SET(&sMemoryPressurePending, false);
-    if (mpPending) {
-      nsCOMPtr<nsIObserverService> os = services::GetObserverService();
-      if (os) {
-        os->NotifyObservers(nsnull, "memory-pressure",
-                            NS_LITERAL_STRING("low-memory").get());
-      }
-      else {
-        NS_WARNING("Can't get observer service!");
-      }
-    }
-  }
-
   bool notifyGlobalObserver = (sGlobalObserver != nsnull);
   if (notifyGlobalObserver) 
     sGlobalObserver->OnProcessNextEvent(this, mayWait && !ShuttingDown(),
                                         mRunningEvent);
 
   nsCOMPtr<nsIThreadObserver> obs = mObserver;
   if (obs)
     obs->OnProcessNextEvent(this, mayWait && !ShuttingDown(), mRunningEvent);

--- a/xpcom/threads/nsThread.h
+++ b/xpcom/threads/nsThread.h
@@ -173,21 +173,9 @@ public:
 private:
   NS_DECL_NSIRUNNABLE
 
   nsCOMPtr<nsIThread> mOrigin;
   nsCOMPtr<nsIRunnable> mSyncTask;
   nsresult mResult;
 };
 
-namespace mozilla {
-
-/**
- * This function causes the main thread to fire a memory pressure event at its
- * next available opportunity.
- *
- * You may call this function from any thread.
- */
-void ScheduleMemoryPressureEvent();
-
-} // namespace mozilla
-
 #endif  // nsThread_h__