Report PPAPI plugin load error code to UMA.

base/native_library_posix.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 <dlfcn.h>
 
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_restrictions.h"
 
 namespace base {
 
 // static
 NativeLibrary LoadNativeLibrary(const FilePath& library_path,
-                                std::string* error) {
+                                NativeLibraryLoadError* error) {
   // dlopen() opens the file off disk.
   base::ThreadRestrictions::AssertIOAllowed();
 
   // We deliberately do not use RTLD_DEEPBIND.  For the history why, please
   // refer to the bug tracker.  Some useful bug reports to read include:
   // http://crbug.com/17943, http://crbug.com/17557, http://crbug.com/36892,
   // and http://crbug.com/40794.
   void* dl = dlopen(library_path.value().c_str(), RTLD_LAZY);
   if (!dl && error)
-    *error = dlerror();
+    error->message = dlerror();
 
   return dl;
 }
 
 // static
 void UnloadNativeLibrary(NativeLibrary library) {
   int ret = dlclose(library);
   if (ret < 0) {
     DLOG(ERROR) << "dlclose failed: " << dlerror();
     NOTREACHED();
   }
 }
 
 // static
 void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
                                           const char* name) {
   return dlsym(library, name);
 }
 
 // static
 string16 GetNativeLibraryName(const string16& name) {
   return ASCIIToUTF16("lib") + name + ASCIIToUTF16(".so");
 }
 
+// static
+std::ostream& operator<<(std::ostream& out,
+                         const NativeLibraryLoadError& error) {
+  return out << error.message;
+}
+
 }  // namespace base