Use PreloadCheckGroup in ExtensionInstallChecker. Make RequirementsChecker a PreloadCheck.

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 3ced48021b8e6666898d05d680b76f9fde1075f3..2177095f82587c6006345e27e319ed66a3294c5c 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -4044,17 +4044,6 @@ From <ph name="DOWNLOAD_DOMAIN">$3<ex>example.com</ex></ph>
       <message name="IDS_APP_CANT_DOWNGRADE_VERSION" desc="Error message when a user tries to install an app with a lower version than a version that it already installed.">
         Attempted to downgrade app.
       </message>
-      <message name="IDS_EXTENSION_WEBGL_NOT_SUPPORTED" desc="Error message when an extension has a requirement for WebGL that the system does not support.">
-        WebGL is not supported.
-      </message>
-      <message name="IDS_EXTENSION_NPAPI_NOT_SUPPORTED" desc="Error message when an extension has a requirement for plugins that the system does not support.">
-        NPAPI plugins are not supported.
-      </message>
-      <if expr="not use_aura">
-        <message name="IDS_EXTENSION_WINDOW_SHAPE_NOT_SUPPORTED" desc="Error message when an extension has a requirement for shaped windows that the system does not support.">
-          Shaped windows are not supported.
-        </message>
-      </if>
       <if expr="chromeos">
         <message name="IDS_EXTENSION_CANT_INSTALL_IN_DEVICE_LOCAL_ACCOUNT" desc="Error message when a user tries to install or the administrator tries to force-install through policy an extension that is not allowed in a device-local account.">
           <ph name="EXTENSION_NAME">$1<ex>Google Talk</ex></ph> (extension ID "<ph name="EXTENSION_ID">$2<ex>nckgahadagoaajjgafhacjanaoiihapd</ex></ph>") is not allowed in this type of session.