Fix for pdf plugin not loaded in the linux sandbox. Also, not showing...

chrome/common/pepper_plugin_registry.cc

 // Copyright (c) 2010 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 "chrome/common/pepper_plugin_registry.h"
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/native_library.h"
 #include "base/path_service.h"
@@ skipping 76 matching lines @@
       plugin.mime_types.push_back(WideToASCII(parts[j]));
 
     plugins->push_back(plugin);
   }
 }
 
 // static
 void PepperPluginRegistry::GetExtraPlugins(
     std::vector<PepperPluginInfo>* plugins) {
   FilePath path;
-  if (PathService::Get(chrome::FILE_PDF_PLUGIN, &path) &&
-      file_util::PathExists(path)) {
+  // We can't check for path existance here, since we are in the sandbox.
+  // If plugin is missing, it will later fail to
+  // load the library and the missing plugin message will be displayed.
+  if (PathService::Get(chrome::FILE_PDF_PLUGIN, &path)) {
     PepperPluginInfo pdf;
     pdf.path = path;
     pdf.name = "Chrome PDF Viewer";
     pdf.mime_types.push_back("application/pdf");
     pdf.file_extensions = "pdf";
     pdf.type_descriptions = "Portable Document Format";
     plugins->push_back(pdf);
   }
 }
 
@@ skipping 67 matching lines @@
   for (size_t i = 0; i < plugins.size(); ++i) {
     const FilePath& path = plugins[i].path;
     ModuleHandle module = pepper::PluginModule::CreateModule(path);
     if (!module) {
       DLOG(ERROR) << "Failed to load pepper module: " << path.value();
       continue;
     }
     modules_[path] = module;
   }
 }