diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/ports/SkOSFile_win.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/ports/SkOSFile_win.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkOSFile.h"
+
+#include "SkTFitsIn.h"
+
+#include <io.h>
+#include <stdio.h>
+#include <sys/stat.h>
+
+typedef struct {
+    ULONGLONG fVolume;
+    ULONGLONG fLsbSize;
+    ULONGLONG fMsbSize;
+} SkFILEID;
+
+static bool sk_ino(SkFILE* f, SkFILEID* id) {
+    int fileno = _fileno((FILE*)f);
+    if (fileno < 0) {
+        return false;
+    }
+
+    HANDLE file = (HANDLE)_get_osfhandle(fileno);
+    if (INVALID_HANDLE_VALUE == file) {
+        return false;
+    }
+
+    //TODO: call GetFileInformationByHandleEx on Vista and later with FileIdInfo.
+    BY_HANDLE_FILE_INFORMATION info;
+    if (0 == GetFileInformationByHandle(file, &info)) {
+        return false;
+    }
+    id->fVolume = info.dwVolumeSerialNumber;
+    id->fLsbSize = info.nFileIndexLow + (((ULONGLONG)info.nFileIndexHigh) << 32);
+    id->fMsbSize = 0;
+
+    return true;
+}
+
+bool sk_fidentical(SkFILE* a, SkFILE* b) {
+    SkFILEID aID, bID;
+    return sk_ino(a, &aID) && sk_ino(b, &bID)
+           && aID.fLsbSize == bID.fLsbSize
+           && aID.fMsbSize == bID.fMsbSize
+           && aID.fVolume == bID.fVolume;
+}
+
+class SkAutoNullKernelHandle : SkNoncopyable {
+public:
+    SkAutoNullKernelHandle(const HANDLE handle) : fHandle(handle) { }
+    ~SkAutoNullKernelHandle() { CloseHandle(fHandle); }
+    operator HANDLE() const { return fHandle; }
+    bool isValid() const { return NULL != fHandle; }
+private:
+    HANDLE fHandle;
+};
+typedef SkAutoNullKernelHandle SkAutoWinMMap;
+
+void sk_fmunmap(const void* addr, size_t) {
+    UnmapViewOfFile(addr);
+}
+
+void* sk_fdmmap(int fileno, size_t* length) {
+    HANDLE file = (HANDLE)_get_osfhandle(fileno);
+    if (INVALID_HANDLE_VALUE == file) {
+        return NULL;
+    }
+
+    LARGE_INTEGER fileSize;
+    if (0 == GetFileSizeEx(file, &fileSize)) {
+        //TODO: use SK_TRACEHR(GetLastError(), "Could not get file size.") to report.
+        return NULL;
+    }
+    if (!SkTFitsIn<size_t>(fileSize.QuadPart)) {
+        return NULL;
+    }
+
+    SkAutoWinMMap mmap(CreateFileMapping(file, NULL, PAGE_READONLY, 0, 0, NULL));
+    if (!mmap.isValid()) {
+        //TODO: use SK_TRACEHR(GetLastError(), "Could not create file mapping.") to report.
+        return NULL;
+    }
+
+    // Eventually call UnmapViewOfFile
+    void* addr = MapViewOfFile(mmap, FILE_MAP_READ, 0, 0, 0);
+    if (NULL == addr) {
+        //TODO: use SK_TRACEHR(GetLastError(), "Could not map view of file.") to report.
+        return NULL;
+    }
+
+    *length = static_cast<size_t>(fileSize.QuadPart);
+    return addr;
+}
+
+int sk_fileno(SkFILE* f) {
+    return _fileno((FILE*)f);
+}
+
+void* sk_fmmap(SkFILE* f, size_t* length) {
+    int fileno = sk_fileno(f);
+    if (fileno < 0) {
+        return NULL;
+    }
+
+    return sk_fdmmap(fileno, length);
+}