[MD History] Create an icons.html for MD History.

ui/webui/resources/cr_elements/icons.html

Index: ui/webui/resources/cr_elements/icons.html
diff --git a/ui/webui/resources/cr_elements/icons.html b/ui/webui/resources/cr_elements/icons.html
index 8e7ee7f413a82d6d3afd69cacc5fd60cb4527912..64f372407b628ffd1237f51f89efa840bd03fde9 100644
--- a/ui/webui/resources/cr_elements/icons.html
+++ b/ui/webui/resources/cr_elements/icons.html
@@ -17,6 +17,7 @@ Do not add rarely used icons here; place those in your application.
 <if expr="chromeos">
       <g id="check"><path d="M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z"></path></g>
 </if>
+      <g id="chevron-left"><path d="M15.41 7.41L14 6l-6 6 6 6 1.41-1.41L10.83 12z"></path></g>

[tsergeant, 2016/05/25 06:49:53]

Actually, this should move into history/icons.html, since it's not used anywhere
else.

       <g id="chevron-right"><path d="M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"></path></g>
       <g id="clear"><path d="M19 6.41L17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z"></path></g>
       <g id="close"><path d="M19 6.41L17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z"></path></g>