Report PPAPI plugin load error code to UMA.

base/native_library_win.cc

 // Copyright (c) 2011 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 "base/native_library.h"
 
+#include <ostream>
+
 #include <windows.h>
 
 #include "base/file_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_restrictions.h"
 
 namespace base {
 
 typedef HMODULE (WINAPI* LoadLibraryFunction)(const wchar_t* file_name);
 
+namespace {
+
 NativeLibrary LoadNativeLibraryHelper(const FilePath& library_path,
                                       LoadLibraryFunction load_library_api,
-                                      std::string* error) {
+                                      NativeLibraryLoadError* error) {
   // LoadLibrary() opens the file off disk.
   ThreadRestrictions::AssertIOAllowed();
 
   // Switch the current directory to the library directory as the library
   // may have dependencies on DLLs in this directory.
   bool restore_directory = false;
   FilePath current_directory;
   if (GetCurrentDirectory(&current_directory)) {
     FilePath plugin_path = library_path.DirName();
     if (!plugin_path.empty()) {
       SetCurrentDirectory(plugin_path);
       restore_directory = true;
     }
   }
 
   HMODULE module = (*load_library_api)(library_path.value().c_str());
   if (!module && error) {
     // GetLastError() needs to be called immediately after |load_library_api|.
-    DWORD last_error = GetLastError();
-    *error = StringPrintf("%u", last_error);
+    error->code = GetLastError();
   }
 
   if (restore_directory)
     SetCurrentDirectory(current_directory);
 
   return module;
 }
 
+}  // namespace
+
 // static
 NativeLibrary LoadNativeLibrary(const FilePath& library_path,
-                                std::string* error) {
+                                NativeLibraryLoadError* error) {
   return LoadNativeLibraryHelper(library_path, LoadLibraryW, error);
 }
 
 NativeLibrary LoadNativeLibraryDynamically(const FilePath& library_path) {
   typedef HMODULE (WINAPI* LoadLibraryFunction)(const wchar_t* file_name);
 
   LoadLibraryFunction load_library;
   load_library = reinterpret_cast<LoadLibraryFunction>(
       GetProcAddress(GetModuleHandle(L"kernel32.dll"), "LoadLibraryW"));
 
   return LoadNativeLibraryHelper(library_path, load_library, NULL);
 }
 
 // static
 void UnloadNativeLibrary(NativeLibrary library) {
   FreeLibrary(library);
 }
 
 // static
 void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
                                           const char* name) {
   return GetProcAddress(library, name);
 }
 
 // static
 string16 GetNativeLibraryName(const string16& name) {
   return name + ASCIIToUTF16(".dll");
 }
 
+// static
+std::ostream& operator<<(std::ostream& out,
+                         const NativeLibraryLoadError& error) {
+  return out << error.code;
+}
+
 }  // namespace base