Add recommended extension installation support

extensions/browser/management_policy.cc

Index: extensions/browser/management_policy.cc
diff --git a/extensions/browser/management_policy.cc b/extensions/browser/management_policy.cc
index 50183d04884cd5596df851ad43c7f58a5aaaf90b..156ba64d456257361a90c0a94107156814b727a4 100644
--- a/extensions/browser/management_policy.cc
+++ b/extensions/browser/management_policy.cc
@@ -47,6 +47,12 @@ bool ManagementPolicy::Provider::MustRemainDisabled(
   return false;
 }
 
+bool ManagementPolicy::Provider::MustRemainInstalled(
+    const Extension* extension,
+    base::string16* error) const {
+  return false;
+}
+
 void ManagementPolicy::RegisterProvider(Provider* provider) {
   providers_.insert(provider);
 }
@@ -57,20 +63,20 @@ void ManagementPolicy::UnregisterProvider(Provider* provider) {
 
 bool ManagementPolicy::UserMayLoad(const Extension* extension,
                                    base::string16* error) const {
-  return ApplyToProviderList(&Provider::UserMayLoad, "Installation",
-                             true, extension, error);
+  return ApplyToProviderList(
+      &Provider::UserMayLoad, "Installation", true, extension, error);
 }
 
 bool ManagementPolicy::UserMayModifySettings(const Extension* extension,
                                              base::string16* error) const {
-  return ApplyToProviderList(&Provider::UserMayModifySettings, "Modification",
-                             true, extension, error);
+  return ApplyToProviderList(
+      &Provider::UserMayModifySettings, "Modification", true, extension, error);
 }
 
 bool ManagementPolicy::MustRemainEnabled(const Extension* extension,
                                          base::string16* error) const {
-  return ApplyToProviderList(&Provider::MustRemainEnabled, "Disabling",
-                             false, extension, error);
+  return ApplyToProviderList(
+      &Provider::MustRemainEnabled, "Disabling", false, extension, error);
 }
 
 bool ManagementPolicy::MustRemainDisabled(const Extension* extension,
@@ -84,6 +90,12 @@ bool ManagementPolicy::MustRemainDisabled(const Extension* extension,
   return false;
 }
 
+bool ManagementPolicy::MustRemainInstalled(const Extension* extension,
+                                           base::string16* error) const {
+  return ApplyToProviderList(
+      &Provider::MustRemainInstalled, "Removing", false, extension, error);
+}
+
 void ManagementPolicy::UnregisterAllProviders() {
   providers_.clear();
 }