Ensure that the DirectWrite font cache works in Chrome canary on Windows 8+ with AppContainer prote…

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 <dwrite.h>
 #include <map>
 #include <string>
 #include <utility>
@@ skipping 903 matching lines @@
 bool FontCollectionLoader::IsFileCached(UINT32 font_key) {
   if (!cache_.get() || cache_->memory() == NULL) {
     return false;
   }
   CacheMap::iterator iter = cache_map_.find(
       GetFontNameFromKey(font_key).c_str());
   return iter != cache_map_.end();;
 }
 
 bool FontCollectionLoader::LoadCacheFile() {
-  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kFontCacheSharedMemSuffix)) {
-    return false;
-  }
-  base::SharedMemory* shared_mem = new base::SharedMemory();
-  std::string name(content::kFontCacheSharedSectionName);
-  name.append(base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-                  switches::kFontCacheSharedMemSuffix));
-  if (!shared_mem->Open(name.c_str(), true))
+  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;
+  base::StringToUint(font_cache_handle_string,
+                     reinterpret_cast<unsigned int*>(&font_cache_handle));
+  DCHECK(font_cache_handle);
+
+  base::SharedMemory* shared_mem = new base::SharedMemory(
+      font_cache_handle, true);
   // Map while file
   shared_mem->Map(0);
 
   cache_.reset(shared_mem);
 
   if (!ValidateAndLoadCacheMap()) {
     cache_.reset();
     return false;
   }
 
@@ skipping 273 matching lines @@
   g_shared_font_cache.Set(mapping);
 
   return true;
 }
 
 bool BuildFontCache(const base::FilePath& file) {
   return BuildFontCacheInternal(file.value().c_str());
 }
 
 }  // namespace content