Revert 158217 - Allow extensions which can run without NPAPI to run under Windows 8 Metro.

chrome/common/extensions/extension.cc

Index: chrome/common/extensions/extension.cc
===================================================================
--- chrome/common/extensions/extension.cc	(revision 158694)
+++ chrome/common/extensions/extension.cc	(working copy)
@@ -1513,7 +1513,6 @@
 bool Extension::LoadPlugins(string16* error) {
   if (!manifest_->HasKey(keys::kPlugins))
     return true;
-
   ListValue* list_value = NULL;
   if (!manifest_->GetList(keys::kPlugins, &list_value)) {
     *error = ASCIIToUTF16(errors::kInvalidPlugins);
@@ -1544,20 +1543,24 @@
       }
     }
 
-    // We don't allow extensions to load NPAPI plugins on Chrome OS, or under
-    // Windows 8 Metro mode, but still parse the entries to display consistent
-    // error messages. If the extension actually requires the plugins then
-    // LoadRequirements will prevent it loading.
 #if defined(OS_CHROMEOS)
-    continue;
-#elif defined(OS_WIN)
+    // We don't allow extension plugins to run on Chrome OS. We still
+    // parse the manifest entry so that error messages are consistently
+    // displayed across platforms.
+#else
+#if defined(OS_WIN)
+    // Like Chrome OS, we don't support NPAPI plugins in Windows 8 metro mode
+    // but in this case we want to fail with an error.
     if (base::win::IsMetroProcess()) {
-      continue;
+      *error = l10n_util::GetStringUTF16(
+          IDS_EXTENSION_INSTALL_PLUGIN_NOT_SUPPORTED);
+      return false;
     }
 #endif  // defined(OS_WIN).
     plugins_.push_back(PluginInfo());
     plugins_.back().path = path().Append(FilePath::FromUTF8Unsafe(path_str));
     plugins_.back().is_public = is_public;
+#endif  // defined(OS_CHROMEOS).
   }
   return true;
 }
@@ -1685,11 +1688,9 @@
 }
 
 bool Extension::LoadRequirements(string16* error) {
-  // Before parsing requirements from the manifest, automatically default the
-  // NPAPI plugin requirement based on whether it includes NPAPI plugins.
-  ListValue* list_value = NULL;
-  requirements_.npapi =
-    manifest_->GetList(keys::kPlugins, &list_value) && !list_value->empty();
+  // If the extension has plugins, then |requirements_.npapi| defaults to true.
+  if (plugins_.size() > 0)
+    requirements_.npapi = true;
 
   if (!manifest_->HasKey(keys::kRequirements))
     return true;