Enforce the 'requirements' field in manifests.

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 83617a4f333fbe3b8a2c0f78b0f220bc48eca505..63324cdf2635b1df027003c3d50cfb6cc8ef7be0 100644
--- a/chrome/browser/extensions/installed_loader.cc
+++ b/chrome/browser/extensions/installed_loader.cc
@@ -76,6 +76,19 @@ void InstalledLoader::Load(const ExtensionInfo& info, bool write_to_prefs) {
         *info.extension_manifest,
         GetCreationFlags(&info),
         &error);
+    if (extension_prefs_->HasUnsupportedRequirements(extension->id())) {
+      std::vector<std::string> requirement_errors =
+          extension_prefs_->GetUnsupportedRequirements(extension->id());
+      extensions::Extension::InstallWarningVector install_warnings;
+      std::vector<std::string>::iterator it;
+      for (it = requirement_errors.begin(); it != requirement_errors.end();
+           ++it) {
+        install_warnings.push_back(Extension::InstallWarning(
+            Extension::InstallWarning::FORMAT_TEXT, *it));
+      }
+      const_cast<Extension*>(extension.get())->AddInstallWarnings(
+          install_warnings);
+    }
   } else {
     error = errors::kManifestUnreadable;
   }