Add a size parameter to SharedMemoryHandle.

sandbox/win/src/process_mitigations_win32k_dispatcher.cc

Index: sandbox/win/src/process_mitigations_win32k_dispatcher.cc
diff --git a/sandbox/win/src/process_mitigations_win32k_dispatcher.cc b/sandbox/win/src/process_mitigations_win32k_dispatcher.cc
index f27711de6f32f844aa964bde80a893de312dfd5c..b44164001bbcde94d0d9a544e1e901f149166a5d 100644
--- a/sandbox/win/src/process_mitigations_win32k_dispatcher.cc
+++ b/sandbox/win/src/process_mitigations_win32k_dispatcher.cc
@@ -21,7 +21,8 @@ namespace sandbox {
 namespace {
 
 base::SharedMemoryHandle GetSharedMemoryHandle(const ClientInfo& client_info,
-                                               HANDLE handle) {
+                                               HANDLE handle,
+                                               size_t size) {
   HANDLE result_handle = nullptr;
   intptr_t handle_int = reinterpret_cast<intptr_t>(handle);
   if (handle_int <= 0 ||
@@ -29,7 +30,7 @@ base::SharedMemoryHandle GetSharedMemoryHandle(const ClientInfo& client_info,
                          &result_handle, 0, FALSE, DUPLICATE_SAME_ACCESS)) {
     result_handle = nullptr;
   }
-  return base::SharedMemoryHandle(result_handle,
+  return base::SharedMemoryHandle(result_handle, size,
                                   base::UnguessableToken::Create());
 }
 
@@ -411,8 +412,8 @@ bool ProcessMitigationsWin32KDispatcher::GetCertificate(
     ipc->return_info.nt_status = STATUS_ACCESS_DENIED;
     return true;
   }
-  base::SharedMemoryHandle handle =
-      GetSharedMemoryHandle(*ipc->client_info, shared_buffer_handle);
+  base::SharedMemoryHandle handle = GetSharedMemoryHandle(
+      *ipc->client_info, shared_buffer_handle, shared_buffer_size);
   if (!handle.IsValid()) {
     ipc->return_info.nt_status = STATUS_ACCESS_DENIED;
     return true;
@@ -516,7 +517,8 @@ bool ProcessMitigationsWin32KDispatcher::ConfigureOPMProtectedOutput(
     return true;
   };
   base::SharedMemoryHandle handle =
-      GetSharedMemoryHandle(*ipc->client_info, shared_buffer_handle);
+      GetSharedMemoryHandle(*ipc->client_info, shared_buffer_handle,
+                            sizeof(DXGKMDT_OPM_CONFIGURE_PARAMETERS));
   if (!handle.IsValid()) {
     ipc->return_info.nt_status = STATUS_ACCESS_DENIED;
     return true;
@@ -547,17 +549,18 @@ bool ProcessMitigationsWin32KDispatcher::GetOPMInformation(
     ipc->return_info.nt_status = STATUS_ACCESS_DENIED;
     return true;
   }
-  base::SharedMemoryHandle handle =
-      GetSharedMemoryHandle(*ipc->client_info, shared_buffer_handle);
+  size_t shared_buffer_size =
+      std::max(sizeof(DXGKMDT_OPM_GET_INFO_PARAMETERS),
+               sizeof(DXGKMDT_OPM_REQUESTED_INFORMATION));
+
+  base::SharedMemoryHandle handle = GetSharedMemoryHandle(
+      *ipc->client_info, shared_buffer_handle, shared_buffer_size);
   if (!handle.IsValid()) {
     ipc->return_info.nt_status = STATUS_ACCESS_DENIED;
     return true;
   }
   base::SharedMemory buffer(handle, false);
 
-  size_t shared_buffer_size =
-      std::max(sizeof(DXGKMDT_OPM_GET_INFO_PARAMETERS),
-               sizeof(DXGKMDT_OPM_REQUESTED_INFORMATION));
   if (!buffer.Map(shared_buffer_size)) {
     ipc->return_info.nt_status = STATUS_ACCESS_DENIED;
     return true;