Enable NPAPI if policy has plugin policies.

chrome/browser/policy/profile_policy_connector.cc

Index: chrome/browser/policy/profile_policy_connector.cc
diff --git a/chrome/browser/policy/profile_policy_connector.cc b/chrome/browser/policy/profile_policy_connector.cc
index 12b5b44e65566fd688605f7ba6298f9cdcd9f62b..1d35cbeaf03855c9e2e169b3e229f109b6a3c27a 100644
--- a/chrome/browser/policy/profile_policy_connector.cc
+++ b/chrome/browser/policy/profile_policy_connector.cc
@@ -7,6 +7,7 @@
 #include <vector>
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
@@ -17,7 +18,10 @@
 #include "components/policy/core/common/configuration_policy_provider.h"
 #include "components/policy/core/common/policy_service_impl.h"
 #include "components/policy/core/common/schema_registry_tracking_policy_provider.h"
+#include "content/public/browser/plugin_service.h"
+#include "content/public/common/content_switches.h"
 #include "google_apis/gaia/gaia_auth_util.h"
+#include "policy/policy_constants.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h"
@@ -129,8 +133,38 @@ void ProfilePolicyConnector::Init(
       connector->SetUserPolicyDelegate(special_user_policy_provider_.get());
   }
 #endif
+
+#if defined(OS_WIN) || defined(OS_MACOSX)
+  EnableNPAPIIfRequired();
+#endif
 }
 
+#if defined(OS_WIN) || defined(OS_MACOSX)
+void ProfilePolicyConnector::EnableNPAPIIfRequired() {

[Mattias Nissler (ping if slow), 2015/04/09 17:15:01]

The canonical way to do this within the policy/prefs framework: You'd have a
policy handler that looks at the policy keys you care about (i.e. the ones
below). You introduce a boolean pref named prefs::kEnableNpapi, which the policy
handler sets to true if any of the policies are set. Then, have some code
register a pref observer on the Profile's PrefService that takes care of making
the appropriate call into content to change the value if appropriate.

+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+
+  if (command_line->HasSwitch(switches::kEnableNpapi))
+    return;
+
+  PolicyNamespace chrome_ns = PolicyNamespace(POLICY_DOMAIN_CHROME, "");
+  const PolicyMap& chrome_policy = policy_service_->GetPolicies(chrome_ns);
+
+  // The list of Plugin related policies that re-enable NPAPI. Remove once NPAPI
+  // is dead.
+  const std::string plugin_policies[] = { key::kEnabledPlugins,
+                                          key::kPluginsAllowedForUrls,
+                                          key::kPluginsBlockedForUrls,
+                                          key::kDisabledPluginsExceptions,
+                                          key::kDisabledPlugins };
+  for (auto policy : plugin_policies) {
+    if (chrome_policy.GetValue(policy)) {
+      content::PluginService::GetInstance()->EnableNpapiPlugins();
+      break;
+    }
+  }
+}
+#endif
+
 void ProfilePolicyConnector::InitForTesting(scoped_ptr<PolicyService> service) {
   policy_service_ = service.Pass();
 }