[MD History] Prevent horizontal scrolling of history views.

This CL fixes an issue where the overlay scrollbar would allow Chrome to
scroll to the right to show the space covered by the vertical scrollbar.
This has been fixed by reverting to overflow:auto.

BUG=638527
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2273523002
Cr-Commit-Position: refs/heads/master@{#414273}

chrome/browser/resources/md_history/app.vulcanized.html

@@ -3630,7 +3630,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     <style include="shared-style">
       :host {
         display: block;
-        overflow: overlay;
+        overflow: auto;
       }
 
       #infinite-list {
@@ -3802,7 +3802,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     <style include="shared-style">
       :host {
         display: block;
-        overflow: overlay;
+        overflow: auto;
       }
 
       #illustration {

chrome/browser/resources/md_history/history_list.html

@@ -11,7 +11,7 @@
     <style include="shared-style">
       :host {
         display: block;
-        overflow: overlay;
+        overflow: auto;
       }
 
       #infinite-list {

chrome/browser/resources/md_history/synced_device_manager.html

@@ -12,7 +12,7 @@
     <style include="shared-style">
       :host {
         display: block;
-        overflow: overlay;
+        overflow: auto;
       }
 
       #illustration {