[Resources] Update the Google logo assets to the proper representations

This will only affect the Local NTP (offline).

Also, in Local NTP use the @2x version and let Chrome downscale it (recommended way, done on the online NTP).

BUG=363519
R=oshima@chromium.org

Review URL: https://codereview.chromium.org/450313002

Cr-Commit-Position: refs/heads/master@{#288409}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288409 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/local_ntp/local_ntp.css

@@ -36,9 +36,7 @@ body.fakebox-disable #fakebox > input {
 }
 
 #logo {
-  background-image: -webkit-image-set(
-      url('images/google_logo.png') 1x,
-      url('images/google_logo.png@2x') 2x);
+  background-image: url('images/google_logo.png@2x');
   background-repeat: no-repeat;
   background-size: 269px 95px;
   height: 95px;
@@ -48,7 +46,7 @@ body.fakebox-disable #fakebox > input {
 }
 
 body.alternate-logo #logo {
-  background-image: url(images/white_google_logo.png);
+  background-image: url('images/white_google_logo.png@2x');
 }
 
 #fakebox {