Make SharedMemoryHandle a class on windows.

content/common/dwrite_font_platform_win.cc

 // Copyright 2014 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.
 
 #include "content/public/common/dwrite_font_platform_win.h"
 
 #include <windows.h>
 
 #include <dwrite.h>
 #include <map>
@@ skipping 919 matching lines @@
   return iter != cache_map_.end();;
 }
 
 bool FontCollectionLoader::LoadCacheFile() {
   std::string font_cache_handle_string =
       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
           switches::kFontCacheSharedHandle);
   if (font_cache_handle_string.empty())
     return false;
 
-  base::SharedMemoryHandle font_cache_handle = NULL;
+  unsigned int handle_int;
   base::StringToUint(font_cache_handle_string,
-                     reinterpret_cast<unsigned int*>(&font_cache_handle));
-  DCHECK(font_cache_handle);
+                     reinterpret_cast<unsigned int*>(&handle_int));

[Tom Sepez, 2015/09/23 22:06:13]

note: technically wrong, this needs to be the address of a real uint, later
check that it fits inside an int and cast to int.

[erikchen, 2015/09/24 00:44:18]

handle_int was a poorly named variable - it was actually a uint already, and the
reinterpret cast is unnecessary. The existing code was...wrong, since it was
reinterpret_casting a HANDLE* to a uint*.

I've renamed to variable to handle_uint, and added a safety check for the
overflow case.

+  DCHECK(handle_int);
+  base::SharedMemoryHandle font_cache_handle(LongToHandle(handle_int),
+                                             base::GetCurrentProcId());
 
   base::SharedMemory* shared_mem = new base::SharedMemory(
       font_cache_handle, true);
   // Map the cache file into memory.
   shared_mem->Map(0);
 
   cache_.reset(shared_mem);
 
   if (base::StartsWith(base::FieldTrialList::FindFullName("LightSpeed"),
                        "PrefetchDWriteFontCache",
@@ skipping 300 matching lines @@
   g_shared_font_cache.Set(mapping);
 
   return true;
 }
 
 bool BuildFontCache(const base::FilePath& file) {
   return BuildFontCacheInternal(file.value().c_str());
 }
 
 }  // namespace content