Add --enable-html-imports commandline switch and about-flags entry.

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 2740e64d377c31b247f809d580347c5ecda93307..5d889e60a306368762521d7d38ee3e7aad921e12 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -6814,6 +6814,12 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_FLAGS_ENABLE_PANELS_DESCRIPTION" desc="Description for the flag to enable Panel windows.">
         Enable Panel windows that open outside of the browser frame. Attempts to open a Panel will open a popup instead if not enabled. Panels are always enabled on the dev and canary channels.
       </message>
+      <message name="IDS_FLAGS_ENABLE_HTML_IMPORTS_NAME" desc="Enable HTML Imports.">
+        Enable HTML Imports
+      </message>
+      <message name="IDS_FLAGS_ENABLE_HTML_IMPORTS_DESCRIPTION" desc="Description of 'Enable HTML Imports' flag.">
+        Enabling this option allows web applications to load HTML Imports.
+      </message>
       <message name="IDS_FLAGS_ENABLE_WEBGL_NAME" desc="Name of the 'Enable WebGL' lab.">
         Enable WebGL
       </message>