Create task_manager namespace and wrap classes related to TaskManager with it.

chrome/browser/task_manager/os_resource_win.cc

Index: chrome/browser/task_manager/os_resource_win.cc
diff --git a/chrome/browser/task_manager/task_manager_os_resources_win.cc b/chrome/browser/task_manager/os_resource_win.cc
similarity index 93%
rename from chrome/browser/task_manager/task_manager_os_resources_win.cc
rename to chrome/browser/task_manager/os_resource_win.cc
index e1e070e1ed48aaa6563847cf85f5db01c6731824..0ca678757089ec26db7aa73ae19d6bd8fb1b9b57 100644
--- a/chrome/browser/task_manager/task_manager_os_resources_win.cc
+++ b/chrome/browser/task_manager/os_resource_win.cc
@@ -2,7 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/task_manager/task_manager_os_resources_win.h"
+#include "chrome/browser/task_manager/os_resource_win.h"
+
+namespace task_manager {
 
 void GetWinGDIHandles(base::ProcessHandle process,
                       size_t* current,
@@ -37,3 +39,5 @@ void GetWinUSERHandles(base::ProcessHandle process,
     CloseHandle(process_with_query_rights);
   }
 }
+
+}  // namespace task_manager