Update network error interstitial strings
+ Updated headings
+ Updated summary paragraph and moved from under details to below the heading.

Reference UI review deck is in the bug description. Implementation screenshots https://code.google.com/p/chromium/issues/detail?id=518975#c8
---
Fixes a bug in the heading in the original CL 1500993002

BUG=518975

Review URL: https://codereview.chromium.org/1583693005

Cr-Commit-Position: refs/heads/master@{#369571}
diff --git a/components/components_chromium_strings.grd b/components/components_chromium_strings.grd
index 9206b036..4f91af9 100644
--- a/components/components_chromium_strings.grd
+++ b/components/components_chromium_strings.grd
@@ -153,19 +153,13 @@
           again for improved performance.
         </message>
       </if>
-
-      <if expr="not is_android and not is_ios">
-        <message name="IDS_ERRORPAGES_SUMMARY_INTERNET_DISCONNECTED" desc="Summary of the error page when the network connection failed. May be followed by platform dependent instructions.">
-          Chromium can't display the webpage because your computer isn't 
-          connected to the Internet.
-        </message>
-      </if>
-
       <message name="IDS_ERRORPAGES_SUGGESTION_FIREWALL_CONFIG_HEADER" desc="When a webpage fails to load, in some cases we suggest reconfiguring the firewall.  This is a header above some details.">
         Allow Chromium to access the network in your firewall or antivirus
         settings.
       </message>
-
+      <message name="IDS_ERRORPAGES_SUMMARY_BLOCKED_ENROLLMENT_CHECK_PENDING" desc="Summary in the error page when the user tries to browse before the forced enrollment check has finished.">
+        Chromium OS hasn’t completed its initial setup.
+      </message>
       <if expr="is_macosx">
         <message name="IDS_ERRORPAGES_SUGGESTION_PROXY_DISABLE_PLATFORM" desc="Mac OSX instructions for disabling use of a proxy server.">
           Go to