MD History: Fix overlapping of sidebar footer in very short windows

chrome/browser/resources/md_history/side_bar.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-a11y-keys-behavior/iron-a11y-keys-behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-selector/iron-selector.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-ripple/paper-ripple.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/color.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/typography.html">
 <link rel="import" href="chrome://history/browser_service.html">
 <link rel="import" href="chrome://history/shared_style.html">
 
 <dom-module id="history-side-bar">
   <template>
     <style include="shared-style">
       :host {
-        display: block;
+        display: flex;
+        flex-direction: column;

[lshang, 2016/10/12 05:15:29]

nit: There is only one single iron-selector element inside of history-side-bar,
so this is probably not needed. The only difference I can see is the position of
iron-icon besides "Clearing browsing data" when the scroll bar shows.

[tsergeant, 2016/10/12 06:06:45]

Done.

         height: 100%;
-        padding-top: 5px;
+        overflow-x: hidden;
+        overflow-y: auto;
         width: var(--side-bar-width);
       }
 
+      :host([drawer]) {
+        height: calc(100% - var(--toolbar-height));

[lshang, 2016/10/12 05:15:29]

nit: could this be calc(100% - var(|height of drawer header|))? Even though
drawer-header's height equals var(--toolbar-height), it would be more clear that
the height of rest side bar part is calculated from the side bar header, within
the same element, not from reference of toolbar element, imo.

[tsergeant, 2016/10/12 06:06:45]

As discussed, I'm leaving this as-is without renaming.

+      }
+
       div.separator {
         background-color: rgba(0, 0, 0, 0.08);
+        flex-shrink: 0;
         height: 1px;
         margin: 8px 0;
       }
 
       #clear-browsing-data {
         justify-content: space-between;
       }
 
       #clear-browsing-data iron-icon {
         -webkit-margin-end: 24px;
         color: var(--paper-grey-400);
         height: 20px;
         margin-bottom: 10px;
         margin-top: 10px;
         width: 20px;
       }
 
       iron-selector {
         -webkit-user-select: none;
         background-color: transparent;
         color: #5a5a5a;
+        display: flex;
+        flex: 1;
+        flex-direction: column;
+        padding-top: 5px;

[lshang, 2016/10/12 05:15:29]

nit: margins between "Tabs from other devices/Clear browsing data" and the
separator line are both 8px, so set padding-top: 8px here probably is better, to
be consistent.

Or you can set it to 10px, as what it is now on tot.

[tsergeant, 2016/10/12 06:06:45]

I've set it to 8px, which matches Settings

       }
 
       iron-selector > a {
         @apply(--paper-font-subhead);
         -webkit-padding-start: 24px;
         align-items: center;
         box-sizing: border-box;
         color: inherit;
         cursor: pointer;
         display: flex;
         font-size: 14px;
         font-weight: 500;
         min-height: 48px;
         position: relative;
         text-decoration: none;
       }
 
       iron-selector > a.iron-selected {
         color: var(--google-blue-500);
-        font-weight: 500;
+      }
+
+      #spacer {
+        flex: 1;
       }
 
       #footer {
-        bottom: 0;
         color: var(--paper-grey-600);
-        position: absolute;
         width: var(--side-bar-width);
       }
 
-      :host([drawer]) #footer {
-        /* This compensates the 120px by which app-drawer protrudes under
-         * the viewport. */
-        bottom: 120px;
-      }
-
       #footer-text {
         -webkit-padding-end: 16px;
         -webkit-padding-start: 24px;
         line-height: 20px;
         margin: 24px 0;
       }
 
       #footer a {
         color: var(--google-blue-700);
         text-decoration: none;
@@ skipping 13 matching lines @@
         $i18n{openTabsMenuItem}
         <paper-ripple></paper-ripple>
       </a>
       <div class="separator"></div>
       <a href="chrome://settings/clearBrowserData"
           on-tap="onClearBrowsingDataTap_" id="clear-browsing-data">
         $i18n{clearBrowsingData}
         <iron-icon icon="cr:open-in-new"></iron-icon>
         <paper-ripple id="cbd-ripple"></paper-ripple>
       </a>
+      <div id="spacer"></div>
       <div id="footer" hidden="[[!showFooter]]">
         <div class="separator"></div>
         <div id="footer-text">$i18nRaw{sidebarFooter}</div>
       </div>
     </iron-selector>
   </template>
   <script src="chrome://history/side_bar.js"></script>
 </dom-module>