Report PPAPI plugin load error code to UMA.

base/native_library.h

 // 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.
 
 #ifndef BASE_NATIVE_LIBRARY_H_
 #define BASE_NATIVE_LIBRARY_H_
 
 // 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"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #elif defined(OS_MACOSX)
 #import <CoreFoundation/CoreFoundation.h>
 #endif  // OS_*
 
@@ skipping 22 matching lines @@
   union {
     CFBundleRef bundle;
     void* dylib;
   };
 };
 typedef NativeLibraryStruct* NativeLibrary;
 #elif defined(OS_POSIX)
 typedef void* NativeLibrary;
 #endif  // OS_*
 
+struct NativeLibraryLoadError {
+#if defined(OS_WIN)
+  NativeLibraryLoadError() : 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
 // you're done.
 // This function retrieves the LoadLibrary function exported from kernel32.dll
 // and calls it instead of directly calling the LoadLibrary function via the
 // import table.
 BASE_EXPORT NativeLibrary LoadNativeLibraryDynamically(
     const FilePath& library_path);
 #endif  // OS_WIN
 
 // Unloads a native library.
 BASE_EXPORT void UnloadNativeLibrary(NativeLibrary library);
 
 // Gets a function pointer from a native library.
 BASE_EXPORT void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
                                                       const char* name);
 
 // Returns the full platform specific name for a native library.
 // For example:
 // "mylib" returns "mylib.dll" on Windows, "libmylib.so" on Linux,
 // "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,

[brettw, 2014/03/24 17:21:25]

The style guide permits operator<< for logging but says "you should try to avoid
these whenever possible". We do this for some of the very common classes we have
that need to be logged frequently. But in this case, it would seem to be just as
clear to add a GetError() member to the NativeLibraryLoadError that returns a
string that people can use for the log messages.

Then you can also remove the extra includes for ios stuff as well.

[xhwang, 2014/03/24 17:53:21]

Done.

+                                     const NativeLibraryLoadError& error);
+
 }  // namespace base
 
 #endif  // BASE_NATIVE_LIBRARY_H_