Make SharedMemoryHandle a class on windows.

content/common/dwrite_font_platform_win.cc

Index: content/common/dwrite_font_platform_win.cc
diff --git a/content/common/dwrite_font_platform_win.cc b/content/common/dwrite_font_platform_win.cc
index f2b4bd93b6043f4e0dadd5db27c8b9cc3e4b4540..e9611a675c7b6d6e5ff41f529b96836629b72245 100644
--- a/content/common/dwrite_font_platform_win.cc
+++ b/content/common/dwrite_font_platform_win.cc
@@ -937,10 +937,12 @@ bool FontCollectionLoader::LoadCacheFile() {
   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);