Enable NPAPI plugins if any plugin policies are set.

content/browser/plugin_service_impl.cc

 // Copyright (c) 2012 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 "content/browser/plugin_service_impl.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_path.h"
@@ skipping 172 matching lines @@
   base::FilePath path =
       command_line->GetSwitchValuePath(switches::kLoadPlugin);
   if (!path.empty())
     AddExtraPluginPath(path);
   path = command_line->GetSwitchValuePath(switches::kExtraPluginDir);
   if (!path.empty())
     PluginList::Singleton()->AddExtraPluginDir(path);
 
   if (command_line->HasSwitch(switches::kDisablePluginsDiscovery))
     PluginList::Singleton()->DisablePluginsDiscovery();
-#if defined(OS_WIN) || defined(OS_MACOSX)
-  npapi_plugins_enabled_ = command_line->HasSwitch(switches::kEnableNpapi);
-  NPAPIPluginStatus status =
-      npapi_plugins_enabled_ ? NPAPI_STATUS_ENABLED : NPAPI_STATUS_DISABLED;
-#else
-  NPAPIPluginStatus status = NPAPI_STATUS_UNSUPPORTED;
-#endif
-  UMA_HISTOGRAM_ENUMERATION("Plugin.NPAPIStatus", status,
-                            NPAPI_STATUS_ENUM_COUNT);
 }
 
 void PluginServiceImpl::StartWatchingPlugins() {
   // Start watching for changes in the plugin list. This means watching
   // for changes in the Windows registry keys and on both Windows and POSIX
   // watch for changes in the paths that are expected to contain plugins.
 #if defined(OS_WIN)
   if (hkcu_key_.Create(HKEY_CURRENT_USER,
                        kRegistryMozillaPlugins,
                        KEY_NOTIFY) == ERROR_SUCCESS) {
@@ skipping 560 matching lines @@
   PluginList::Singleton()->RemoveExtraPluginPath(path);
 }
 
 void PluginServiceImpl::AddExtraPluginDir(const base::FilePath& path) {
   PluginList::Singleton()->AddExtraPluginDir(path);
 }
 
 void PluginServiceImpl::RegisterInternalPlugin(
     const WebPluginInfo& info,
     bool add_at_beginning) {
-  if (!NPAPIPluginsSupported() &&
-      info.type == WebPluginInfo::PLUGIN_TYPE_NPAPI) {
+  // Internal plugins should never be NPAPI.
+  DCHECK_NE(info.type, WebPluginInfo::PLUGIN_TYPE_NPAPI);

[jam, 2015/02/19 23:46:48]

nit: i'd make that a CHECK_NE

[Will Harris, 2015/02/20 03:55:50]

Done.

+  if (info.type == WebPluginInfo::PLUGIN_TYPE_NPAPI) {
     DVLOG(0) << "Don't register NPAPI plugins when they're not supported";
     return;
   }
   PluginList::Singleton()->RegisterInternalPlugin(info, add_at_beginning);
 }
 
 void PluginServiceImpl::UnregisterInternalPlugin(const base::FilePath& path) {
   PluginList::Singleton()->UnregisterInternalPlugin(path);
 }
 
 void PluginServiceImpl::GetInternalPlugins(
     std::vector<WebPluginInfo>* plugins) {
   PluginList::Singleton()->GetInternalPlugins(plugins);
 }
 
 bool PluginServiceImpl::NPAPIPluginsSupported() {
+  static bool command_line_checked = false;
+
+  if (!command_line_checked) {
+#if defined(OS_WIN) || defined(OS_MACOSX)
+    const base::CommandLine* command_line =
+        base::CommandLine::ForCurrentProcess();
+    npapi_plugins_enabled_ = command_line->HasSwitch(switches::kEnableNpapi);
+    NPAPIPluginStatus status =
+        npapi_plugins_enabled_ ? NPAPI_STATUS_ENABLED : NPAPI_STATUS_DISABLED;
+#else
+    NPAPIPluginStatus status = NPAPI_STATUS_UNSUPPORTED;
+#endif
+    UMA_HISTOGRAM_ENUMERATION("Plugin.NPAPIStatus", status,
+        NPAPI_STATUS_ENUM_COUNT);
+  }
+
   return npapi_plugins_enabled_;
 }
 
 void PluginServiceImpl::DisablePluginsDiscoveryForTesting() {
   PluginList::Singleton()->DisablePluginsDiscovery();
 }
 
 void PluginServiceImpl::EnableNpapiPluginsForTesting() {
   npapi_plugins_enabled_ = true;
 }
@@ skipping 46 matching lines @@
 #endif
 
 bool PluginServiceImpl::PpapiDevChannelSupported(
     BrowserContext* browser_context,
     const GURL& document_url) {
   return content::GetContentClient()->browser()->
       IsPluginAllowedToUseDevChannelAPIs(browser_context, document_url);
 }
 
 }  // namespace content