Report PPAPI plugin load error code to UMA.

base/native_library_win.cc

Index: base/native_library_win.cc
diff --git a/base/native_library_win.cc b/base/native_library_win.cc
index bcea485a1d10582016622738f1081fde471cd567..5db3dcddb99d190cfa49879b8556071b1d68de63 100644
--- a/base/native_library_win.cc
+++ b/base/native_library_win.cc
@@ -17,7 +17,7 @@ typedef HMODULE (WINAPI* LoadLibraryFunction)(const wchar_t* file_name);
 
 NativeLibrary LoadNativeLibraryHelper(const FilePath& library_path,
                                       LoadLibraryFunction load_library_api,
-                                      std::string* error) {
+                                      NativeLibraryLoadError* error) {
   // LoadLibrary() opens the file off disk.
   ThreadRestrictions::AssertIOAllowed();
 
@@ -36,8 +36,7 @@ NativeLibrary LoadNativeLibraryHelper(const FilePath& library_path,
   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 = GetLastError();
   }
 
   if (restore_directory)
@@ -48,7 +47,7 @@ NativeLibrary LoadNativeLibraryHelper(const FilePath& library_path,
 
 // static
 NativeLibrary LoadNativeLibrary(const FilePath& library_path,
-                                std::string* error) {
+                                NativeLibraryLoadError* error) {
   return LoadNativeLibraryHelper(library_path, LoadLibraryW, error);
 }
 
@@ -59,7 +58,7 @@ NativeLibrary LoadNativeLibraryDynamically(const FilePath& library_path) {
   load_library = reinterpret_cast<LoadLibraryFunction>(
       GetProcAddress(GetModuleHandle(L"kernel32.dll"), "LoadLibraryW"));
 
-  return LoadNativeLibraryHelper(library_path, load_library, NULL);
+  return LoadNativeLibraryHelper(library_path, load_library, NULL, NULL);
 }
 
 // static