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..f68bb6f921c39920b8ee8d5aff925335ebb37ddb 100644
--- a/base/native_library.h
+++ b/base/native_library.h
@@ -8,6 +8,8 @@
 // This file defines a cross-platform "NativeLibrary" type which represents
 // a loadable module.
 
+#include <iosfwd>
+
 #include "base/base_export.h"
 #include "base/compiler_specific.h"
 #include "build/build_config.h"
@@ -50,11 +52,20 @@ typedef NativeLibraryStruct* NativeLibrary;
 typedef void* NativeLibrary;
 #endif  // OS_*
 
+struct NativeLibraryLoadError {
+#if defined(OS_WIN)
+  NativeLibraryLoadError() : error_code(0) {}
+  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
@@ -79,6 +90,10 @@ BASE_EXPORT void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
 // "mylib.dylib" on Mac.
 BASE_EXPORT string16 GetNativeLibraryName(const string16& name);
 
+// Stream operator so NativeLibraryLoadError can be used in log statements.
+BASE_EXPORT std::ostream& operator<<(std::ostream& out,
+                                     const NativeLibraryLoadError& error);
+
 }  // namespace base
 
 #endif  // BASE_NATIVE_LIBRARY_H_