MD Downloads: fix some a11y issues

chrome/browser/resources/md_downloads/item.html

Index: chrome/browser/resources/md_downloads/item.html
diff --git a/chrome/browser/resources/md_downloads/item.html b/chrome/browser/resources/md_downloads/item.html
index ca33797dc18ef88ff93bff75bffb71dd1d7fcc32..975f10997c17908b5ac38dcd72f81733eb712f14 100644
--- a/chrome/browser/resources/md_downloads/item.html
+++ b/chrome/browser/resources/md_downloads/item.html
@@ -30,7 +30,7 @@
       }
 
       #date {
-        color: rgb(104, 113, 116);
+        color: rgb(103, 112, 115);

[calamity, 2016/12/09 01:31:42]

Is this a remnant from the old blue-grey color days? Should we ask Alan if we
can just make this grey?

[Dan Beam, 2016/12/09 02:03:54]

talked with bettes@, says it's cool to use grey 700 here and in settings

         font-size: 100%;
         font-weight: 500;
         margin: 24px auto 10px;
@@ -154,7 +154,7 @@
       }
 
       .is-active #url {
-        color: #969696;
+        color: var(--paper-grey-600);
       }
 
       #progress,
@@ -211,7 +211,7 @@
       }
 
       #remove {
-        color: #969696;
+        color: var(--paper-grey-600);
         font-size: 16px;
         height: 32px;
         line-height: 17px;  /* TODO(dbeam): why is this necesssary? */