Add back buttons and load new 'pages' by calling javascript.

build/android/pylib/results/presentation/javascript/main_html.js

Index: build/android/pylib/results/presentation/javascript/main_html.js
diff --git a/build/android/pylib/results/presentation/javascript/main_html.js b/build/android/pylib/results/presentation/javascript/main_html.js
index 6c254d5a6885ffdae66f9422161f0a9ebc031954..71f22b7094e053c97205ac7e47441bd07429a251 100644
--- a/build/android/pylib/results/presentation/javascript/main_html.js
+++ b/build/android/pylib/results/presentation/javascript/main_html.js
@@ -26,6 +26,18 @@ function showTestTable(show_the_table) {
         show_the_table ? 'table' : 'none');
 }
 
+function showBackButtons(show_buttons) {
+    buttons = document.getElementsByClassName('back_button')
+    Array.prototype.slice.call(buttons)
+      .forEach(function(button) {
+        if (!show_buttons) {
+          button.style.display = 'none';
+        } else {
+          button.style.display = 'inline';
+        }
+      });
+}
+
 function showTestsOfOneSuiteOnly(suite_name) {
   setTitle('Test Results of Suite: ' + suite_name)
   show_all = (suite_name == 'TOTAL')
@@ -46,12 +58,16 @@ function showTestsOfOneSuiteOnly(suite_name) {
       });
   showTestTable(true);
   showSuiteTable(false);
+  showBackButtons(true);
+  window.scrollTo(0, 0);
 }
 
 function showSuiteTableOnly() {
   setTitle('Suites Summary')
   showTestTable(false);
   showSuiteTable(true);
+  showBackButtons(false);
+  window.scrollTo(0, 0);
 }
 
 function setTitle(title) {
@@ -166,17 +182,6 @@ function sortByColumn(head) {
   }
 }
 
-function loadPage() {
-  var args = getArguments();
-  if ('suite' in args) {
-    // The user wants to visit detailed 'subpage' of that suite.
-    showTestsOfOneSuiteOnly(args['suite']);
-  } else {
-    // The user wants to visit the summary of all suites.
-    showSuiteTableOnly();
-  }
-}
-
 function reportIssues() {
   var url = 'https://bugs.chromium.org/p/chromium/issues/entry?' +
             'labels=Pri-2,Type-Bug,Restrict-View-Google&' +