Remove unused NTP strings.

- IDS_NTP_CUSTOM* were added in https://crrev.com/569519 and may have
  never been used.
- IDS_NTP_DOWNLOAD* went unused as of https://crrev.com/647035.

Change-Id: I1aa26d46c3d903d604bee218d5b2bf5da2afb14f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2135530Reviewed-by: Natalie Chouinard <chouinard@chromium.org>
Reviewed-by: Kyle Milka <kmilka@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756389}

chrome/app/generated_resources.grd

@@ -5314,9 +5314,6 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_NTP_CUSTOM_LINKS_INVALID_URL" desc="Error message for when an invalid URL is provided while creating a custom link. (On the New Tab Page)">
        Type a valid URL
       </message>
-      <message name="IDS_NTP_CUSTOM_LINKS_SHORTCUT_EXISTS" desc="Error message for when the shortcut being created already exists. (On the New Tab Page)">
-       Shortcut already exists
-      </message>
       <message name="IDS_NTP_CUSTOM_LINKS_CANT_CREATE" desc="A catchall error message for when the shortcut cannot be created. (On the New Tab Page)">
        Can’t create shortcut
       </message>
@@ -5350,9 +5347,6 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_NTP_CUSTOM_BG_DAILY_REFRESH" desc="The text label for the daily background randomization option.  (On the New Tab Page)">
         Refresh daily
       </message>
-      <message name="IDS_NTP_CUSTOM_BG_SURPRISE_ME" desc="The text label for the random background option. (On the New Tab Page)">
-        Surprise me
-      </message>
       <message name="IDS_NTP_CUSTOM_BG_RESTORE_DEFAULT" desc="The text label for the restore default option for background customization. (On the New Tab Page)">
         Restore default background
       </message>
@@ -5371,12 +5365,6 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_NTP_CUSTOM_BG_BACKGROUNDS_UNAVAILABLE" desc="Error message for when background customization is not available. (On the New Tab Page)">
         Backgrounds are unavailable. Try again later.
       </message>
-      <message name="IDS_NTP_CUSTOM_BG_IMAGE_UNAVAILABLE" desc="Error message for when the selected background image is not available. (On the New Tab Page)">
-        Image is unavailable. Try again later.
-      </message>
-      <message name="IDS_NTP_CUSTOM_BG_IMAGE_NOT_USABLE" desc="Error message for when an uploaded image is not usuable as a custom background. (On the New Tab Page)">
-        This image can't be used. Choose a different image.
-      </message>
       <message name="IDS_NTP_CUSTOM_BG_BACK_LABEL" desc="Accessibility label for the back arrow on the background picker dialog. (On the New Tab Page)">
         Back
       </message>
@@ -9815,15 +9803,6 @@ Please help our engineers fix this problem. Tell us what happened right before y
         </message>
     </if>
 
-    <!-- NTP content suggestions strings -->
-    <message name="IDS_NTP_DOWNLOAD_SUGGESTIONS_SECTION_HEADER" desc="Header of the downloads section, which is a list of pages (or files) that the user downloaded, displayed as cards on the New Tab Page.">
-      Downloads
-    </message>
-
-    <message name="IDS_NTP_DOWNLOADS_SUGGESTIONS_SECTION_EMPTY" desc="On the New Tab Page, text of card explaining to the user that they can expect to see some download related content suggestions in this section in the future.">
-      Your downloads appear here
-    </message>
-
     <!-- Automation infobar -->
     <message name="IDS_CONTROLLED_BY_AUTOMATION" desc="Message shown when the browser session is being controlled by an automated test.">
       Chrome is being controlled by automated test software.

chrome/app/generated_resources_grd/IDS_NTP_CUSTOM_BG_IMAGE_NOT_USABLE.png.sha1

-a00ae14f0391125309431b19754e9dd98ec6a077
\ No newline at end of file

chrome/app/generated_resources_grd/IDS_NTP_CUSTOM_BG_IMAGE_UNAVAILABLE.png.sha1

-f44d352720276759cf0bca00f2e8ca535598ea0f
\ No newline at end of file

chrome/app/generated_resources_grd/IDS_NTP_CUSTOM_BG_SURPRISE_ME.png.sha1

-9e4b43a9def96c3b3dd6f562c278d43054fc513e
\ No newline at end of file

chrome/app/generated_resources_grd/IDS_NTP_CUSTOM_LINKS_SHORTCUT_EXISTS.png.sha1

-147ee16ed56f8ace5184978152a02cd13af01e44
\ No newline at end of file