MD History: Add responsive layout which hides the sidebar in thin windows

ui/webui/resources/cr_elements/cr_toolbar/cr_toolbar.html

Index: ui/webui/resources/cr_elements/cr_toolbar/cr_toolbar.html
diff --git a/ui/webui/resources/cr_elements/cr_toolbar/cr_toolbar.html b/ui/webui/resources/cr_elements/cr_toolbar/cr_toolbar.html
index 29c59a485c34db66a873e68f69ca0ca67e34123e..f24214b508fe8604cd655b61fcd2a893f0226e3a 100644
--- a/ui/webui/resources/cr_elements/cr_toolbar/cr_toolbar.html
+++ b/ui/webui/resources/cr_elements/cr_toolbar/cr_toolbar.html
@@ -11,35 +11,58 @@
         height: 56px;
       }
 
+      #menuButton {
+        height: 32px;
+        margin: 6px 6px 6px 18px;
+        min-width: 32px;
+        padding: 6px;
+        width: 32px;
+      }
+
       h1 {
         @apply(--layout-flex);
-        -webkit-padding-start: 24px;
         font-size: 123%;
         font-weight: 400;
       }
 
       #leftContent {
+        -webkit-padding-end: 24px;
         align-items: center;
         display: flex;
-        width: var(--side-bar-width, 0);
       }
 
       #centeredContent {
         -webkit-padding-end: 12px;
+        align-items: center;
         display: flex;
         flex: 1 1 0;
-        justify-content: center;
+        height: 100%;
+        position: relative;
       }
 
       :host([narrow_]) #centeredContent {
         justify-content: flex-end;
       }
 
+      #search {
+        position: absolute;
+      }
+
+      :host([narrow_]) #search {
+        position: static;
+      }
+
       :host([narrow_][showing-search_]) #leftContent {
         display: none;
       }
+
+      :host([narrow_][showing-search_]) #centeredContent {
+        -webkit-margin-start: 18px;
+      }
     </style>
     <div id="leftContent">
+      <paper-icon-button id="menuButton" icon="cr:menu" on-click="onMenuClick_">
+      </paper-icon-button>
       <h1>[[pageName]]</h1>
     </div>