Report PPAPI plugin load error code to UMA.

base/native_library_posix.cc

Index: base/native_library_posix.cc
diff --git a/base/native_library_posix.cc b/base/native_library_posix.cc
index dfa20fc01cf78ef6ab2061f3eefb32d3c8f324c0..88525bf126fc4d37a89205e6033efdf858fe0cdd 100644
--- a/base/native_library_posix.cc
+++ b/base/native_library_posix.cc
@@ -15,7 +15,8 @@ namespace base {
 
 // static
 NativeLibrary LoadNativeLibrary(const FilePath& library_path,
-                                std::string* error) {
+                                std::string* error_message,
+                                uint32* error_code) {
   // dlopen() opens the file off disk.
   base::ThreadRestrictions::AssertIOAllowed();
 
@@ -24,8 +25,8 @@ NativeLibrary LoadNativeLibrary(const FilePath& library_path,
   // 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();
+  if (!dl && error_message)
+    *error_message = dlerror();
 
   return dl;
 }