--- a/gfx/ycbcr/ycbcr_to_rgb565.cpp
+++ b/gfx/ycbcr/ycbcr_to_rgb565.cpp
@@ -33,88 +33,23 @@
  * and other provisions required by the GPL or the LGPL. If you do not delete
  * the provisions above, a recipient may use your version of this file under
  * the terms of any one of the MPL, the GPL or the LGPL.
  *
  * ***** END LICENSE BLOCK ***** */
 
 #include "ycbcr_to_rgb565.h"
 
-//The logic for have_ycbcr_to_rgb565 is taken from pixman-cpu.c
-
-#if !defined (HAVE_ARM_NEON)
+#if !defined (MOZILLA_MAY_SUPPORT_NEON)
 
 int have_ycbcr_to_rgb565 ()
 {
     return 0;
 }
 
 #else
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/mman.h>
-#include <fcntl.h>
-#include <elf.h>
-
-#ifdef ANDROID
-
 int have_ycbcr_to_rgb565 ()
 {
-    static int have_ycbcr_to_rgb565_initialized = 0;
-    static int arm_has_neon = 0;
-    if (!have_ycbcr_to_rgb565_initialized)
-    {
-        have_ycbcr_to_rgb565_initialized = 1;
-
-        char buf[1024];
-        const char* ver_token = "CPU architecture: ";
-        FILE* f = fopen("/proc/cpuinfo", "r");
-        if (!f) {
-	        return 0;
-        }
-
-        fread(buf, sizeof(char), 1024, f);
-        arm_has_neon = strstr(buf, "neon") != NULL;
-        fclose(f);
-    }
-    return arm_has_neon;
+    return mozilla::supports_neon();
 }
 
-#else
-
-int have_ycbcr_to_rgb565 ()
-{
-    static int have_ycbcr_to_rgb565_initialized = 0;
-    static int arm_has_neon = 0;
-    if (!have_ycbcr_to_rgb565_initialized)
-    {
-        have_ycbcr_to_rgb565_initialized = 1;
-        int fd;
-        Elf32_auxv_t aux;
-
-        fd = open ("/proc/self/auxv", O_RDONLY);
-        if (fd >= 0)
-        {
-            while (read (fd, &aux, sizeof(Elf32_auxv_t)) == sizeof(Elf32_auxv_t))
-            {
-                if (aux.a_type == AT_HWCAP)
-                {
-                    uint32_t hwcap = aux.a_un.a_val;
-                    arm_has_neon = (hwcap & 4096) != 0;
-                    break;
-                }
-            }
-            close (fd);
-         }
-    }
-
-    return arm_has_neon;
-}
-
-#endif //ANDROID
-
-#endif //_MSC_VER
-
+#endif //MOZILLA_MAY_SUPPORT_NEON

--- a/gfx/ycbcr/ycbcr_to_rgb565.h
+++ b/gfx/ycbcr/ycbcr_to_rgb565.h
@@ -1,5 +1,10 @@
 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
+#ifndef MEDIA_BASE_YCBCR_TO_RGB565_H_
+#define MEDIA_BASE_YCBCR_TO_RGB565_H_
+#include "mozilla/arm.h"
 
 int have_ycbcr_to_rgb565();
+
+#endif // MEDIA_BASE_YCBCR_TO_RGB565_H_

--- a/xpcom/glue/Makefile.in
+++ b/xpcom/glue/Makefile.in
@@ -127,16 +127,17 @@ EXPORTS_mozilla = \
   CondVar.h \
   DeadlockDetector.h \
   FileUtils.h \
   GenericFactory.h \
   IntentionalCrash.h \
   Monitor.h \
   Mutex.h \
   SSE.h \
+  arm.h \
   unused.h \
   $(NULL)
 
 EXPORTS_mozilla/threads = \
   nsThreadIDs.h \
   $(NULL)
 
 SDK_LIBRARY     =                        \

new file mode 100644
--- /dev/null
+++ b/xpcom/glue/arm.cpp
@@ -0,0 +1,200 @@
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * 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 arm.cpp
+ *
+ * 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):
+ *   Timothy B. Terriberry <tterriberry@mozilla.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+/* compile-time and runtime tests for whether to use various ARM extensions */
+
+#include "arm.h"
+
+namespace {
+
+// arm.h has parallel #ifs which declare MOZILLA_ARM_HAVE_CPUID_DETECTION.
+// We don't check it here so that we get compile errors if it's defined, but
+// we don't compile one of these detection methods. The detection code here is
+// based on the CPU detection in libtheora.
+
+#if defined(_MSC_VER)
+//For GetExceptionCode() and EXCEPTION_ILLEGAL_INSTRUCTION.
+#  define WIN32_LEAN_AND_MEAN
+#  define WIN32_EXTRA_LEAN
+#  include <windows.h>
+
+static bool
+check_edsp(void)
+{
+#  if defined(MOZILLA_MAY_SUPPORT_EDSP)
+  __try
+  {
+    //PLD [r13]
+    __emit(0xF5DDF000);
+    return true;
+  }
+  __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
+  {
+    //Ignore exception.
+  }
+#  endif
+  return false;
+}
+
+static bool
+check_armv6(void)
+{
+#  if defined(MOZILLA_MAY_SUPPORT_ARMV6)
+  __try
+  {
+    //SHADD8 r3,r3,r3
+    __emit(0xE6333F93);
+    return true;
+  }
+  __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
+  {
+    //Ignore exception.
+  }
+#  endif
+  return false;
+}
+
+static bool
+check_neon(void)
+{
+#  if defined(MOZILLA_MAY_SUPPORT_NEON)
+  __try
+  {
+    //VORR q0,q0,q0
+    __emit(0xF2200150);
+    return true;
+  }
+  __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
+  {
+    //Ignore exception.
+  }
+#  endif
+  return false;
+}
+
+#elif defined(__linux__) || defined(ANDROID)
+#  include <stdio.h>
+#  include <stdlib.h>
+#  include <string.h>
+
+enum{
+  MOZILLA_HAS_EDSP_FLAG=1,
+  MOZILLA_HAS_ARMV6_FLAG=2,
+  MOZILLA_HAS_NEON_FLAG=4
+};
+
+static unsigned
+get_arm_cpu_flags(void)
+{
+  unsigned  flags;
+  FILE     *fin;
+  flags = 0;
+  /*Reading /proc/self/auxv would be easier, but that doesn't work reliably on
+    Android. This also means that detection will fail in Scratchbox, which is
+    desirable, as NEON does not work in the qemu shipped with the Maemo 5 SDK.
+    I don't know if /proc/self/auxv would do any better in that case, anyway,
+    or if it would return random flags from the host CPU.*/
+  fin = fopen ("/proc/cpuinfo","r");
+  if (fin != NULL)
+  {
+    /*512 should be enough for anybody (it's even enough for all the flags that
+      x86 has accumulated... so far).*/
+    char buf[512];
+    while (fgets(buf, 511, fin) != NULL)
+    {
+      if (memcmp(buf, "Features", 8) == 0)
+      {
+        char *p;
+        p = strstr(buf, " edsp");
+        if (p != NULL && (p[5] == ' ' || p[5] == '\n'))
+          flags |= MOZILLA_HAS_EDSP_FLAG;
+        p = strstr(buf, " neon");
+        if( p != NULL && (p[5] == ' ' || p[5] == '\n'))
+          flags |= MOZILLA_HAS_NEON_FLAG;
+      }
+      if (memcmp(buf, "CPU architecture:", 17) == 0)
+      {
+        int version;
+        version = atoi(buf + 17);
+        if (version >= 6)
+          flags |= MOZILLA_HAS_ARMV6_FLAG;
+      }
+    }
+    fclose(fin);
+  }
+  return flags;
+}
+
+// Cache a local copy so we only have to read /proc/cpuinfo once.
+static unsigned arm_cpu_flags = get_arm_cpu_flags();
+
+static bool
+check_edsp(void)
+{
+  return (arm_cpu_flags & MOZILLA_HAS_EDSP_FLAG) != 0;
+}
+
+static bool
+check_armv6(void)
+{
+  return (arm_cpu_flags & MOZILLA_HAS_ARMV6_FLAG) != 0;
+}
+
+static bool
+check_neon(void)
+{
+  return (arm_cpu_flags & MOZILLA_HAS_NEON_FLAG) != 0;
+}
+
+#endif
+
+}
+
+namespace mozilla {
+  namespace arm_private {
+#if defined(MOZILLA_ARM_HAVE_CPUID_DETECTION)
+#if !defined(MOZILLA_PRESUME_EDSP)
+    bool edsp_enabled = check_edsp();
+#endif
+#if !defined(MOZILLA_PRESUME_ARMV6)
+    bool armv6_enabled = check_armv6();
+#endif
+#if !defined(MOZILLA_PRESUME_NEON)
+    bool neon_enabled = check_neon();
+#endif
+#endif
+  } // namespace arm_private
+} // namespace mozilla

new file mode 100644
--- /dev/null
+++ b/xpcom/glue/arm.h
@@ -0,0 +1,180 @@
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * 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 arm.h
+ *
+ * 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):
+ *   Timothy B. Terriberry <tterriberry@mozilla.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+/* compile-time and runtime tests for whether to use SSE instructions */
+
+#ifndef mozilla_arm_h_
+#define mozilla_arm_h_
+
+// for definition of NS_COM_GLUE
+#include "nscore.h"
+
+/* This is patterned after SSE.h, but provides ARMv5E, ARMv6, and NEON
+   detection. For reasons similar to the SSE code, code using NEON (even just
+   in inline asm) needs to be in a separate compilation unit from the regular
+   code, because it requires an ".fpu neon" directive which can't be undone.
+   ARMv5E and ARMv6 code may also require an .arch directive, since by default
+   the assembler refuses to generate code for opcodes outside of its current
+   .arch setting.
+
+   TODO: Add Thumb, Thumb2, VFP, iwMMX, etc. detection, if we need it. */
+
+#if defined(__GNUC__) && defined(__arm__)
+
+#  define MOZILLA_ARM_ARCH 3
+
+#  if defined(__ARM_ARCH_4__) || defined(__ARM_ARCH_4T__) \
+   || defined(_ARM_ARCH_4)
+#    undef MOZILLA_ARM_ARCH
+#    define MOZILLA_ARM_ARCH 4
+#  endif
+
+#  if defined(__ARM_ARCH_5__) || defined(__ARM_ARCH_5T__) \
+   || defined(__ARM_ARCH_5E__) || defined(__ARM_ARCH_5TE__) \
+   || defined(__ARM_ARCH_5TEJ__) || defined(_ARM_ARCH_5)
+#    undef MOZILLA_ARM_ARCH
+#    define MOZILLA_ARM_ARCH 5
+#  endif
+
+#  if defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) \
+   || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) \
+   || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) \
+   || defined(__ARM_ARCH_6M__) || defined(_ARM_ARCH_6)
+#    undef MOZILLA_ARM_ARCH
+#    define MOZILLA_ARM_ARCH 6
+#  endif
+
+#  if defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) \
+   || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) \
+   || defined(__ARM_ARCH_7EM__) || defined(_ARM_ARCH_7)
+#    undef MOZILLA_ARM_ARCH
+#    define MOZILLA_ARM_ARCH 7
+#  endif
+
+
+#  if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95)
+#    define MOZILLA_MAY_SUPPORT_EDSP 1
+#  endif
+
+#  if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
+#    if defined(HAVE_ARM_SIMD)
+#      define MOZILLA_MAY_SUPPORT_ARMV6 1
+#    endif
+#  endif
+
+  // Technically 4.2.x only works in the CodeSourcery releases, but I don't
+  // know how to detect those separately from mainline gcc (which got support
+  // in 4.3). The Maemo version 5 SDK shipped with the CodeSourcery 4.2.1
+  // release, which we need to work.
+#  if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 2)
+#    if defined(HAVE_ARM_NEON)
+#      define MOZILLA_MAY_SUPPORT_NEON 1
+#    endif
+#  endif
+
+  // Currently we only have CPU detection for Linux via /proc/cpuinfo
+#  if defined(__linux__) || defined(ANDROID)
+#    define MOZILLA_ARM_HAVE_CPUID_DETECTION 1
+#  endif
+
+#elif defined(_MSC_VER) && defined(_M_ARM)
+
+#  define MOZILLA_ARM_HAVE_CPUID_DETECTION 1
+  // I don't know how to do arch detection at compile time for MSVC, so assume
+  // the worst for now.
+#  define MOZILLA_ARM_ARCH 3
+
+  // MSVC only allows external asm for ARM, so we don't have to rely on
+  // compiler support.
+#  define MOZILLA_MAY_SUPPORT_EDSP 1
+#  if defined(HAVE_ARM_SIMD)
+#    define MOZILLA_MAY_SUPPORT_ARMV6 1
+#  endif
+#  if defined(HAVE_ARM_SIMD)
+#    define MOZILLA_MAY_SUPPORT_NEON 1
+#  endif
+
+#endif
+
+namespace mozilla {
+
+  namespace arm_private {
+#if defined(MOZILLA_ARM_HAVE_CPUID_DETECTION)
+#if !defined(MOZILLA_PRESUME_EDSP)
+    extern bool NS_COM_GLUE edsp_enabled;
+#endif
+#if !defined(MOZILLA_PRESUME_ARMV6)
+    extern bool NS_COM_GLUE armv6_enabled;
+#endif
+#if !defined(MOZILLA_PRESUME_NEON)
+    extern bool NS_COM_GLUE neon_enabled;
+#endif
+#endif
+  }
+
+#if defined(MOZILLA_PRESUME_EDSP)
+#  define MOZILLA_MAY_SUPPORT_EDSP 1
+  inline bool supports_edsp() { return true; }
+#elif defined(MOZILLA_MAY_SUPPORT_EDSP) \
+   && defined(MOZILLA_ARM_HAVE_CPUID_DETECTION)
+  inline bool supports_edsp() { return arm_private::edsp_enabled; }
+#else
+  inline bool supports_edsp() { return false; }
+#endif
+
+#if defined(MOZILLA_PRESUME_ARMV6)
+#  define MOZILLA_MAY_SUPPORT_ARMV6 1
+  inline bool supports_armv6() { return true; }
+#elif defined(MOZILLA_MAY_SUPPORT_ARMV6) \
+   && defined(MOZILLA_ARM_HAVE_CPUID_DETECTION)
+  inline bool supports_armv6() { return arm_private::armv6_enabled; }
+#else
+  inline bool supports_armv6() { return false; }
+#endif
+
+#if defined(MOZILLA_PRESUME_NEON)
+#  define MOZILLA_MAY_SUPPORT_NEON 1
+  inline bool supports_neon() { return true; }
+#elif defined(MOZILLA_MAY_SUPPORT_NEON) \
+   && defined(MOZILLA_ARM_HAVE_CPUID_DETECTION)
+  inline bool supports_neon() { return arm_private::neon_enabled; }
+#else
+  inline bool supports_neon() { return false; }
+#endif
+
+}
+
+#endif /* !defined(mozilla_arm_h_) */

--- a/xpcom/glue/nomozalloc/Makefile.in
+++ b/xpcom/glue/nomozalloc/Makefile.in
@@ -64,17 +64,17 @@ CPPSRCS		= \
 		nsStringAPI.cpp \
 		GenericModule.cpp \
 		$(NULL)
 
 SDK_LIBRARY     =                        \
 		$(LIB_PREFIX)xpcomglue_s_nomozalloc.$(LIB_SUFFIX) \
 		$(NULL)
 
-GARBAGE += $(CSRCS) $(CPPSRCS) DeadlockDetector.h SSE.h
+GARBAGE += $(CSRCS) $(CPPSRCS) DeadlockDetector.h SSE.h arm.h
 
 # we don't want the shared lib, but we want to force the creation of a static lib.
 FORCE_STATIC_LIB = 1
 
 # Force use of PIC
 FORCE_USE_PIC	= 1
 
 # Pretend we're statically linking the CRT, even though we might not be: this
@@ -89,16 +89,16 @@ include $(topsrcdir)/config/rules.mk
 
 ifdef _MSC_VER
 # Don't include directives about which CRT to use
 OS_COMPILE_CXXFLAGS += -Zl
 OS_COMPILE_CFLAGS += -Zl
 DEFINES += -D_USE_ANSI_CPP
 endif
 
-export:: $(XPCOM_GLUE_SRC_CSRCS) $(XPCOM_GLUE_SRC_CPPSRCS) $(XPCOM_GLUENS_SRC_CPPSRCS) $(topsrcdir)/xpcom/glue/nsStringAPI.cpp $(topsrcdir)/xpcom/glue/GenericModule.cpp $(topsrcdir)/xpcom/glue/DeadlockDetector.h $(topsrcdir)/xpcom/glue/SSE.h
+export:: $(XPCOM_GLUE_SRC_CSRCS) $(XPCOM_GLUE_SRC_CPPSRCS) $(XPCOM_GLUENS_SRC_CPPSRCS) $(topsrcdir)/xpcom/glue/nsStringAPI.cpp $(topsrcdir)/xpcom/glue/GenericModule.cpp $(topsrcdir)/xpcom/glue/DeadlockDetector.h $(topsrcdir)/xpcom/glue/SSE.h $(topsrcdir)/xpcom/glue/arm.h
 	$(INSTALL) $^ .
 
 ifdef TARGET_XPCOM_ABI
 DEFINES += -DTARGET_XPCOM_ABI=\"$(TARGET_XPCOM_ABI)\"
 endif
 
 DEFINES += -DMOZ_NO_MOZALLOC

--- a/xpcom/glue/objs.mk
+++ b/xpcom/glue/objs.mk
@@ -70,16 +70,17 @@ XPCOM_GLUE_SRC_LCPPSRCS =        \
   $(NULL)
 
 XPCOM_GLUE_SRC_CPPSRCS = $(addprefix $(topsrcdir)/xpcom/glue/, $(XPCOM_GLUE_SRC_LCPPSRCS))
 
 XPCOM_GLUENS_SRC_LCPPSRCS =      \
   BlockingResourceBase.cpp       \
   DeadlockDetector.cpp           \
   SSE.cpp                        \
+  arm.cpp                        \
   unused.cpp                     \
   nsProxyRelease.cpp             \
   nsTextFormatter.cpp            \
   GenericFactory.cpp             \
   FileUtils.cpp                  \
   $(NULL)
 
 XPCOM_GLUENS_SRC_CPPSRCS = $(addprefix $(topsrcdir)/xpcom/glue/,$(XPCOM_GLUENS_SRC_LCPPSRCS))