Add --enable-panels flag to about:flags.

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 94b007e25ce75b670a398a3ec5bf543cd6b74a62..17099d5cb8fa8c4e1efdca7b6a000320ffa756ef 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -4376,6 +4376,13 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_FLAGS_ENABLE_ADDITIONAL_AUTOFILL_FEEDBACK_DESCRIPTION" desc="Description for the flag to enable prompts for Autofill feedback">
         Help improve Autofill.  With this enabled, Chrome will occasionally prompt you to send additional feedback to the Autofill team.
       </message>
+      <message name="IDS_FLAGS_ENABLE_PANELS_NAME" desc="Name of the 'Enable Pane
+ls' lab.">
+	Panels
+      </message>
+      <message name="IDS_FLAGS_ENABLE_PANELS_DESCRIPTION" desc="Description of the 'Enable Panels' lab.">

[Dmitry Titov, 2011/07/08 20:59:51]

Most of other flags are wording this as "Description for the flag to enable ..."

+	Enable panel windows in the UI. Warning: Panel windows are currently under development and may not be fully functional.

[Dmitry Titov, 2011/07/08 20:59:51]

I think we can remove this 'Warning', this is kind of obvious that it's an
experiment.

We can also say it's scoped to extensions, like "Enable Chrome Extensions to
open Panel windows outside of browser frame."

+      </message>
 
       <!-- Crashes -->
       <message name="IDS_CRASHES_TITLE" desc="Title for the chrome://crashes page.">