win: Fix x64 compile error in handle writer

minidump/minidump_handle_writer.cc

Index: minidump/minidump_handle_writer.cc
diff --git a/minidump/minidump_handle_writer.cc b/minidump/minidump_handle_writer.cc
index 3d8a969ee7b71b7963fac9e09a5c54453d4a2a5f..6ec7e2e0dfa9344b26f0f870290bc3158401bcea 100644
--- a/minidump/minidump_handle_writer.cc
+++ b/minidump/minidump_handle_writer.cc
@@ -20,6 +20,7 @@
 #include "base/stl_util.h"
 #include "minidump/minidump_extensions.h"
 #include "util/file/file_writer.h"
+#include "util/numeric/safe_assignment.h"
 
 namespace crashpad {
 
@@ -76,7 +77,12 @@ bool MinidumpHandleDataWriter::Freeze() {
 
   handle_data_stream_base_.SizeOfHeader = sizeof(handle_data_stream_base_);
   handle_data_stream_base_.SizeOfDescriptor = sizeof(handle_descriptors_[0]);
-  handle_data_stream_base_.NumberOfDescriptors = handle_descriptors_.size();
+  size_t handle_count = handle_descriptors_.size();
+  if (!AssignIfInRange(&handle_data_stream_base_.NumberOfDescriptors,
+                       handle_count)) {

[Mark Mentovai, 2015/10/21 22:19:26]

You didn’t need handle_count, but if you want to keep it because it’s used in
the LOG below, make it const.

[scottmg, 2015/10/21 22:35:53]

Yeah, was for the LOG. Done.

+    LOG(ERROR) << "handle_count " << handle_count << " out of range";
+    return false;
+  }
   handle_data_stream_base_.Reserved = 0;
 
   return true;