MD Settings: Allow copying text to clipboard from the About page.

chrome/browser/resources/settings/about_page/detailed_build_info.html

Index: chrome/browser/resources/settings/about_page/detailed_build_info.html
diff --git a/chrome/browser/resources/settings/about_page/detailed_build_info.html b/chrome/browser/resources/settings/about_page/detailed_build_info.html
index e31872cd81cc760d5443ab693dd7f705f37f8566..786831aab3d37627c2ad7723f5d1cabb02b8940a 100644
--- a/chrome/browser/resources/settings/about_page/detailed_build_info.html
+++ b/chrome/browser/resources/settings/about_page/detailed_build_info.html
@@ -10,7 +10,11 @@
 
 <dom-module id="settings-detailed-build-info">
   <template>
-    <style include="settings-shared"></style>
+    <style include="settings-shared">
+      .secondary {
+        -webkit-user-select: text;
+      }
+    </style>
     <div class="settings-box two-line">
       <div class="start">
         <!-- TODO(dpapad): Localize string -->