linux: scan more plugin directories, fix bugs

base/native_library_linux.cc

 // Copyright (c) 2009 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.
 
 #include "base/native_library.h"
 
 #include <dlfcn.h>
 
 #include "base/file_path.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 
 namespace base {
 
 // static
 NativeLibrary LoadNativeLibrary(const FilePath& library_path) {
   void* dl = dlopen(library_path.value().c_str(), RTLD_LAZY);
   if (!dl) {
-    LOG(ERROR) << "dlopen failed when trying to open " << library_path.value()
-               << ": " << dlerror();
+    std::string error_message = dlerror();
+    // Some obsolete plugins depend on libxul or libxpcom.
+    // Ignore the error messages when failing to load these.
+    if (error_message.find("libxul.so") == std::string::npos &&
+        error_message.find("libxpcom.so") == std::string::npos) {
+      LOG(ERROR) << "dlopen failed when trying to open " << library_path.value()
+                 << ": " << error_message;
+    }
   }
 
   return dl;
 }
 
 // static
 void UnloadNativeLibrary(NativeLibrary library) {
   int ret = dlclose(library);
   if (ret < 0) {
     LOG(ERROR) << "dlclose failed: " << dlerror();
     NOTREACHED();
   }
 }
 
 // static
 void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
                                           const char* name) {
   return dlsym(library, name);
 }
 
 // static
 string16 GetNativeLibraryName(const string16& name) {
   return ASCIIToUTF16("lib") + name + ASCIIToUTF16(".so");
 }
 
 }  // namespace base