Increase load of blink_perf.paint to reduce flakiness

third_party/WebKit/PerformanceTests/Paint/color-changes.html

Index: third_party/WebKit/PerformanceTests/Paint/color-changes.html
diff --git a/third_party/WebKit/PerformanceTests/Paint/color-changes.html b/third_party/WebKit/PerformanceTests/Paint/color-changes.html
index 3ed433d400e5e3a85eb2a41928f948faa0097a1c..a18e675eb3f2b9a94ae7f13ed44fde03c7d1316e 100644
--- a/third_party/WebKit/PerformanceTests/Paint/color-changes.html
+++ b/third_party/WebKit/PerformanceTests/Paint/color-changes.html
@@ -3,7 +3,6 @@
 <script src="../resources/runner.js"></script>
 <style>
   span {
-    background-color: white;
     padding: 1px;
   }
   .changeColor {
@@ -14,29 +13,43 @@
 // This test measures the lifecycle update performance of changing background
 // colors in large trees.
 
-function buildTree(parent, depth, arity, createElementCallback) {
+function buildTree(parent, depth, arity, tagNameCallback, createElementCallback) {
   for (var child = 0; child < arity; child++) {
-    var element = document.createElement('span');
+    var element = document.createElement(tagNameCallback(depth));
     parent.appendChild(element);
     createElementCallback(element, depth);
     if (depth > 1)
-      buildTree(element, depth - 1, arity, createElementCallback);
+      buildTree(element, depth - 1, arity, tagNameCallback, createElementCallback);
   }
 }
 
-// Build a tall tree (depth=10) that is skinny (arity=2). A middle layer of
+// Build a tall tree that is skinny. A middle layer of
 // the tree should have the changeColor class.
-buildTree(document.body, 11, 2, function(element, depth) {
-  if (depth == 5)
-    element.setAttribute('class', 'changeColor');
-});
+buildTree(document.body, 15, 2,
+  function(depth) {
+    // Use divs at upper levels to avoid too much layout time.
+    return depth > 9 ? 'div' : 'span';
+  },
+  function(element, depth) {
+    element.style.backgroundColor = 'green';
+    if (depth == 5)
+      element.setAttribute('class', 'changeColor');
+  }
+);
 
-// Build a short tree (depth=6) that is fat (arity=4). A middle layer of
+// Build a short tree that is fat. A middle layer of
 // the tree should have the changeColor class.
-buildTree(document.body, 6, 4, function(element, depth) {
-  if (depth == 3)
-    element.setAttribute('class', 'changeColor');
-});
+buildTree(document.body, 6, 7,
+  function(depth) {
+    // Use divs at upper levels to avoid too much layout time.
+    return depth > 4 ? 'div' : 'span';
+  },
+  function(element, depth) {
+    element.style.backgroundColor = 'orange';
+    if (depth == 3)
+      element.setAttribute('class', 'changeColor');
+  }
+);
 
 var runCount = 0;
 var elementsToChange = document.getElementsByClassName('changeColor');