Ensure syncer::internal::GetComputerName returns a UTF-8 string.

Prior to this change, on Windows, GetComputerName resulted in a call to
GetComputerNameA, which returns an ANSI string (not ASCII, not UTF-8).
Call GetComputerNameW instead and convert the returned wide string to
UTF-8.

Tested by adding U+00AB to the computer name.  Saw in about:sync the
name contained a U+FFFD instead (symbol for unrepresentable character).
Performed sync dashboard clear, applied patch, saw that the name
correctly contained U+00AB.

This CL does not address corrupted device info that's already in the
field.  Depending on impact that may be addressed in a future CL.

BUG=406470

Review URL: https://codereview.chromium.org/479703004

Cr-Commit-Position: refs/heads/master@{#292466}

3 files changed, 15 insertions, 4 deletions

diff --git a/sync/util/get_session_name.cc b/sync/util/get_session_name.cc
index 3a09c51..c669e22 100644
--- a/sync/util/get_session_name.cc
+++ b/sync/util/get_session_name.cc
@@ -8,6 +8,7 @@
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/location.h"
+#include "base/strings/string_util.h"
 #include "base/sys_info.h"
 #include "base/task_runner.h"
 
@@ -53,6 +54,7 @@ std::string GetSessionNameSynchronously() {
   if (session_name == "Unknown" || session_name.empty())
     session_name = base::SysInfo::OperatingSystemName();
 
+  DCHECK(base::IsStringUTF8(session_name));
   return session_name;
 }
 
diff --git a/sync/util/get_session_name.h b/sync/util/get_session_name.h
index 724ae3c..7ac34ad 100644
--- a/sync/util/get_session_name.h
+++ b/sync/util/get_session_name.h
@@ -17,6 +17,7 @@ class TaskRunner;
 
 namespace syncer {
 
+// Invokes |done_callback| with the session name, a UTF-8 string.
 SYNC_EXPORT void GetSessionName(
     const scoped_refptr<base::TaskRunner>& task_runner,
     const base::Callback<void(const std::string&)>& done_callback);
diff --git a/sync/util/get_session_name_win.cc b/sync/util/get_session_name_win.cc
index 101bcd4..58980a3 100644
--- a/sync/util/get_session_name_win.cc
+++ b/sync/util/get_session_name_win.cc
@@ -4,16 +4,24 @@
 
 #include "sync/util/get_session_name_win.h"
 
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/strings/utf_string_conversions.h"
+
 #include <windows.h>
 
 namespace syncer {
 namespace internal {
 
 std::string GetComputerName() {
-  char computer_name[MAX_COMPUTERNAME_LENGTH + 1];
-  DWORD size = sizeof(computer_name);
-  if (GetComputerNameA(computer_name, &size))
-    return computer_name;
+  wchar_t computer_name[MAX_COMPUTERNAME_LENGTH + 1] = {0};
+  DWORD size = arraysize(computer_name);
+  if (::GetComputerNameW(computer_name, &size)) {
+    std::string result;
+    bool conversion_successful = base::WideToUTF8(computer_name, size, &result);
+    DCHECK(conversion_successful);
+    return result;
+  }
   return std::string();
 }