Use title case for verbose "Not Secure" omnibox state on Mac.

components/omnibox_strings.grdp

Index: components/omnibox_strings.grdp
diff --git a/components/omnibox_strings.grdp b/components/omnibox_strings.grdp
index a5d080db5235d01b543c86b8dc42b32ad5f58958..407322df69a834dd47d3ab39b26bd5958a537802 100644
--- a/components/omnibox_strings.grdp
+++ b/components/omnibox_strings.grdp
@@ -17,9 +17,16 @@
   <message name="IDS_SECURE_VERBOSE_STATE" desc="An adjective or short adjective phrase shown next to the green lock icon in the omnibox to describe a secure site (valid HTTPS connection). Note that 'secure' in this case primarily refers to HTTPS connection security, so prefer translations with a connotation of 'private' (no one can intercept your communication with the site) rather than 'trustworthy' (which would be a judgment of site reputation). This phrase takes away space from the URL in the omnibox, so it should ideally be as short as possible while staying accurate. This phrase should also make sense compared to the companion phrase 'Not Secure'." meaning="Omnibox phrase to describe a secure site.">
     Secure
   </message>
-  <message name="IDS_NOT_SECURE_VERBOSE_STATE" desc="An adjective or short adjective phrase shown next to the security indicator icon in the omnibox to describe a site that is not secure (unencrypted HTTP or invalid HTTPS connection). Note that 'not secure' in this case primarily refers to HTTPS connection security, so prefer translations with a connotation of 'not private' (someone can intercept your communication with the site) rather than 'not trustworthy' (which would be a judgment of site reputation). This phrase takes away space from the URL in the omnibox, so it should ideally be as short as possible while staying accurate. This phrase should also make sense compared to the companion phrase 'Secure'." meaning="Omnibox phrase to describe a site that is not secure.">
-    Not Secure
-  </message>
+  <if expr="not use_titlecase">
+    <message name="IDS_NOT_SECURE_VERBOSE_STATE" desc="An adjective or short adjective phrase shown next to the security indicator icon in the omnibox to describe a site that is not secure (unencrypted HTTP or invalid HTTPS connection). Note that 'not secure' in this case primarily refers to HTTPS connection security, so prefer translations with a connotation of 'not private' (someone can intercept your communication with the site) rather than 'not trustworthy' (which would be a judgment of site reputation). This phrase takes away space from the URL in the omnibox, so it should ideally be as short as possible while staying accurate. This phrase should also make sense compared to the companion phrase 'Secure'." meaning="Omnibox phrase to describe a site that is not secure.">
+      Not secure
+    </message>
+  </if>
+  <if expr="use_titlecase">
+    <message name="IDS_NOT_SECURE_VERBOSE_STATE" desc="An adjective or short adjective phrase shown next to the security indicator icon in the omnibox to describe a site that is not secure (unencrypted HTTP or invalid HTTPS connection). Note that 'not secure' in this case primarily refers to HTTPS connection security, so prefer translations with a connotation of 'not private' (someone can intercept your communication with the site) rather than 'not trustworthy' (which would be a judgment of site reputation). This phrase takes away space from the URL in the omnibox, so it should ideally be as short as possible while staying accurate. This phrase should also make sense compared to the companion phrase 'Secure'." meaning="Omnibox phrase to describe a site that is not secure.">
+      Not Secure
+    </message>
+  </if>
   <message name="IDS_DANGEROUS_VERBOSE_STATE" desc="Text for the Dangerous Omnibox Verbose State. Displayed when the current page fails the malware check.">
     Dangerous
   </message>