Add comments for struct members that were changed from size_t to uin32_t or uint64_t for IPC safety.

chrome/browser/task_management/sampling/task_group.cc

 // Copyright 2015 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 "chrome/browser/task_management/sampling/task_group.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/stl_util.h"
 #include "build/build_config.h"
@@ skipping 170 matching lines @@
 
 void TaskGroup::RefreshGpuMemory(
     const content::GPUVideoMemoryUsageStats& gpu_memory_stats) {
   auto itr = gpu_memory_stats.process_map.find(process_id_);
   if (itr == gpu_memory_stats.process_map.end()) {
     gpu_memory_ = -1;
     gpu_memory_has_duplicates_ = false;
     return;
   }
 
-  gpu_memory_ = static_cast<int64_t>(itr->second.video_memory);
+  gpu_memory_ = itr->second.video_memory;
   gpu_memory_has_duplicates_ = itr->second.has_duplicates;
 }
 
 void TaskGroup::RefreshWindowsHandles() {
 #if defined(OS_WIN)
   GetWindowsHandles(process_handle_,
                     &gdi_current_handles_,
                     &gdi_peak_handles_,
                     &user_current_handles_,
                     &user_peak_handles_);
@@ skipping 34 matching lines @@
 }
 #endif  // defined(OS_LINUX)
 
 void TaskGroup::OnProcessPriorityDone(bool is_backgrounded) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
   is_backgrounded_ = is_backgrounded;
 }
 
 }  // namespace task_management