Report PPAPI plugin load error code to UMA.

base/native_library.h

Index: base/native_library.h
diff --git a/base/native_library.h b/base/native_library.h
index d7513d0b050e181b4df913e276b39051aef5318f..1e764da89aa6846c4d5b646a301d0d28ad9de799 100644
--- a/base/native_library.h
+++ b/base/native_library.h
@@ -8,8 +8,11 @@
 // This file defines a cross-platform "NativeLibrary" type which represents
 // a loadable module.
 
+#include <string>
+
 #include "base/base_export.h"
 #include "base/compiler_specific.h"
+#include "base/strings/string16.h"
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
@@ -18,8 +21,6 @@
 #import <CoreFoundation/CoreFoundation.h>
 #endif  // OS_*
 
-#include "base/strings/string16.h"
-
 namespace base {
 
 class FilePath;
@@ -50,11 +51,26 @@ typedef NativeLibraryStruct* NativeLibrary;
 typedef void* NativeLibrary;
 #endif  // OS_*
 
+struct BASE_EXPORT NativeLibraryLoadError {
+#if defined(OS_WIN)
+  NativeLibraryLoadError() : code(0) {}
+#endif  // OS_WIN
+
+  // Returns a string representation of the load error.
+  std::string ToString() const;
+
+#if defined(OS_WIN)
+  DWORD code;
+#else
+  std::string message;
+#endif  // OS_WIN
+};
+
 // Loads a native library from disk.  Release it with UnloadNativeLibrary when
 // you're done.  Returns NULL on failure.
-// If |error| is not NULL, it may be filled in with an error message on error.
+// If |error| is not NULL, it may be filled in on load error.
 BASE_EXPORT NativeLibrary LoadNativeLibrary(const FilePath& library_path,
-                                            std::string* error);
+                                            NativeLibraryLoadError* error);
 
 #if defined(OS_WIN)
 // Loads a native library from disk.  Release it with UnloadNativeLibrary when