Fix accessibility in Windows x64 build.

ui/views/win/hwnd_message_handler.cc

Index: ui/views/win/hwnd_message_handler.cc
diff --git a/ui/views/win/hwnd_message_handler.cc b/ui/views/win/hwnd_message_handler.cc
index 70ad075a7b7e5820829e490228bbcea3bde65de8..1d776352b0f4d208660488ec00db540999625ef4 100644
--- a/ui/views/win/hwnd_message_handler.cc
+++ b/ui/views/win/hwnd_message_handler.cc
@@ -1415,9 +1415,11 @@ LRESULT HWNDMessageHandler::OnGetObject(UINT message,
                                         WPARAM w_param,
                                         LPARAM l_param) {
   LRESULT reference_result = static_cast<LRESULT>(0L);
+  // Explicitly cast to DWORD for 64-bit support.
+  DWORD obj_id = static_cast<DWORD>(l_param);

[jschuh, 2014/06/13 23:49:27]

Sorry to be pedantic, but this is an undefined conversion, so it would blow up
on e.g. lexan. You should actually just leave l_param as it is and expand
OBJID_CLIENT as follows:

static const LPARAM kObjIdClient = static_cast<ULONG>(OBJID_CLIENT);

[dmazzoni, 2014/06/15 07:56:03]

OK.

 
   // Accessibility readers will send an OBJID_CLIENT message
-  if (OBJID_CLIENT == l_param) {
+  if (OBJID_CLIENT == obj_id) {

[jschuh, 2014/06/13 23:49:27]

This would become:

if (kObjIdClient == obj_id) {

[dmazzoni, 2014/06/15 07:56:03]

Done.

     // Retrieve MSAA dispatch object for the root view.
     base::win::ScopedComPtr<IAccessible> root(
         delegate_->GetNativeViewAccessible());