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..f78c0c23fc7e34d9aa49e45e3f3b3eb983fdedaa 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) {
+                                      uint32* error_code) {
   // LoadLibrary() opens the file off disk.
   ThreadRestrictions::AssertIOAllowed();
 
@@ -34,10 +34,9 @@ NativeLibrary LoadNativeLibraryHelper(const FilePath& library_path,
   }
 
   HMODULE module = (*load_library_api)(library_path.value().c_str());
-  if (!module && error) {
+  if (!module && error_code) {
     // 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)
@@ -48,8 +47,9 @@ NativeLibrary LoadNativeLibraryHelper(const FilePath& library_path,
 
 // static
 NativeLibrary LoadNativeLibrary(const FilePath& library_path,
-                                std::string* error) {
-  return LoadNativeLibraryHelper(library_path, LoadLibraryW, error);
+                                std::string* /* error_message */,
+                                uint32* error_code) {
+  return LoadNativeLibraryHelper(library_path, LoadLibraryW, error_code);
 }
 
 NativeLibrary LoadNativeLibraryDynamically(const FilePath& library_path) {