Enable loading native libraries with RTLD_DEEPBIND

base/native_library.h

Index: base/native_library.h
diff --git a/base/native_library.h b/base/native_library.h
index b4f3a3cd1ba267000848b09c0ee9d8af7983387f..074b6a70adf343d06e3a0f8bac17f3ded2136903 100644
--- a/base/native_library.h
+++ b/base/native_library.h
@@ -65,12 +65,29 @@ struct BASE_EXPORT NativeLibraryLoadError {
 #endif  // OS_WIN
 };
 
+struct BASE_EXPORT NativeLibraryOptions {

[Primiano Tucci (use gerrit), 2016/08/24 22:14:09]

If there are no other use cases this IMHO should be just an enum or a bitfield
(long arg +  constants to be or-ed) .

[Ken Rockot(use gerrit already), 2016/08/24 23:23:57]

I'd prefer to use a struct here only because it's more easily extensible to
non-boolean option types, and because (to me anyway) it seems easier to read and
understand code which uses actual types instead of integer bitfields. I don't
feel strongly about this though, so if you really want me to change it I will :)

[Primiano Tucci (use gerrit), 2016/08/25 10:20:44]

I leave this to base owners, as I'm not an owner here. No particularly strong
opinion, I just tend to keep things as simple as possible unless there is a use
case and refactor later if I need something fancier..

+  NativeLibraryOptions() {}
+
+  // If |true| the library will prefer its own symbols in lieu of symbols in the
+  // global scope. This is ignored on non-POSIX platforms. On POSIX the behavior
+  // when |true| corresponds to setting RTLD_DEEPBIND on dlopen().

[Primiano Tucci (use gerrit), 2016/08/24 22:14:09]

Interestingly it seems that on Mac OSX DEEPBIND is tthe default behavior.
I didn't test it but from [1] I read "Note: This doesn't apply to Mac OS* X
where the default is the RTLD_DEEPBIND behavior."

https://software.intel.com/en-us/articles/ensuring-shared-library-uses-intel-...

[Ken Rockot(use gerrit already), 2016/08/24 23:23:57]

Added a note about this

+  bool prefer_own_symbols = false;
+};
+
 // 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 on load error.
 BASE_EXPORT NativeLibrary LoadNativeLibrary(const FilePath& library_path,
                                             NativeLibraryLoadError* error);
 
+// 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 on load error.
+BASE_EXPORT NativeLibrary LoadNativeLibraryWithOptions(
+    const FilePath& library_path,
+    const NativeLibraryOptions& options,
+    NativeLibraryLoadError* error);
+
 #if defined(OS_WIN)
 // Loads a native library from disk.  Release it with UnloadNativeLibrary when
 // you're done.