Add UMA logging of extension creation flags.

chrome/browser/extensions/installed_loader.cc

Index: chrome/browser/extensions/installed_loader.cc
diff --git a/chrome/browser/extensions/installed_loader.cc b/chrome/browser/extensions/installed_loader.cc
index 5470083162d4047e6c08175135cd948292f1b101..64118746b9f0cfdd3f6d84a7c8ca7d8170d18fc2 100644
--- a/chrome/browser/extensions/installed_loader.cc
+++ b/chrome/browser/extensions/installed_loader.cc
@@ -115,6 +115,18 @@ BackgroundPageType GetBackgroundPageType(const Extension* extension) {
   return EVENT_PAGE;
 }
 
+// Records the creation flags of an extension grouped by
+// Extension::InitFromValueFlags.
+void RecordCreationFlags(const Extension* extension) {
+  for (int i = 0; i < Extension::kInitFromValueFlagBits; ++i) {
+    int flag = 1 << i;
+    if (extension->creation_flags() & flag) {
+      UMA_HISTOGRAM_ENUMERATION(
+          "Extensions.LoadCreationFlags", i, Extension::kInitFromValueFlagBits);
+    }
+  }
+}
+
 }  // namespace
 
 InstalledLoader::InstalledLoader(ExtensionService* extension_service)
@@ -410,6 +422,8 @@ void InstalledLoader::LoadAllExtensions() {
     if (extensions::ManagedModeInfo::IsContentPack(ex->get()))
       ++content_pack_count;
 
+    RecordCreationFlags(*ex);
+
     extension_service_->RecordPermissionMessagesHistogram(
         ex->get(), "Extensions.Permissions_Load");
   }