MD Extensions: Show messages for no extensions, and for no search results

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 82a8b4eb5e50347698e7d7fbf7a23c0190d0b220..436388b33cc230702b8a4407bad7f230f9b235f7 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -4317,6 +4317,12 @@ From <ph name="DOWNLOAD_DOMAIN">$3<ex>example.com</ex></ph>
         <message name="IDS_MD_EXTENSIONS_LOAD_ERROR_RETRY" desc="The text on the button to retry loading an unpacked extension after a failed load.">
           Retry
         </message>
+        <message name="IDS_MD_EXTENSIONS_MSG_NO_EXT_OR_APP" desc="The text to display when there are no extensions installed.">

[Devlin, 2017/07/07 00:48:07]

nit: to display where?

[scottchen, 2017/07/07 23:08:42]

Done.

+          Find extensions and apps in the <ph name="BEGIN_LINK">&lt;a target="_blank" href="https://chrome.google.com/webstore/category/extensions"&gt;</ph>Chrome Web Store<ph name="END_LINK">&lt;/a&gt;<ex>&lt;/a&gt;</ex></ph>
+        </message>
+        <message name="IDS_MD_EXTENSIONS_MSG_NOT_FOUND" desc="The text to display when there are no search results">

[Devlin, 2017/07/07 00:48:07]

similarly, no search results where?

[scottchen, 2017/07/07 23:08:42]

Done.

+          Search results not found

[Devlin, 2017/07/07 00:48:07]

nit: "Search results not found" sounds funny to me.  Maybe "No results" or "No
matches"?  Do we have similar strings anywhere else?

[scottchen, 2017/07/07 23:08:42]

Settings and downloads both say "No Search Results Found" (I wanted to match
those but I manually typed it wrong). Does "No Search Results Found" sound okay?

[Devlin, 2017/07/10 20:23:53]

Yep, consistency is always good. :)

+        </message>
         <message name="IDS_MD_EXTENSIONS_PACK_DIALOG_TITLE" desc="The title of the dialog to pack an extension.">
           Pack extension
         </message>