pepper: don't warn if PDF plugin is unavailable

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 83 matching lines @@
     for (size_t j = 1; j < parts.size(); ++j)
       plugin.mime_types.push_back(parts[j]);
 
     plugins->push_back(plugin);
   }
 }
 
 // static
 void PepperPluginRegistry::GetExtraPlugins(
     std::vector<PepperPluginInfo>* plugins) {
+  // Once we're sandboxed, we can't know if the PDF plugin is
+  // available or not; but this function is always called once before
+  // we're sandboxed.  So the first time through test if the file is
+  // available and then skip the check on subsequent calls if not.
+  static bool skip_pdf_plugin = false;
   FilePath 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)) {
+  if (!skip_pdf_plugin && PathService::Get(chrome::FILE_PDF_PLUGIN, &path)) {
+    if (!file_util::PathExists(path)) {
+      skip_pdf_plugin = true;
+      return;
+    }
+
     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;
   }
 }