Introduce "testFunction" to reduce boilerplate in extensions API tests....

chrome/test/data/extensions/api_test/bookmarks/test.js

 // bookmarks api test
 // browser_tests.exe --gtest_filter=ExtensionApiTest.Bookmarks
 
 var expected = [
   {"children": [
     {"children": [], "id": "1", "parentId": "0", "index": 0, "title":"Bookmarks bar"},
     {"children": [], "id": "2", "parentId": "0", "index": 1, "title":"Other bookmarks"}
     ],
    "id": "0", "title": ""
   }
@@ skipping 34 matching lines @@
     }
     result = compareTrees(left[i].children, right[i].children);
     if (result !== true)
       return result;
   }
   return true;
 }
 
 var tests = [
   function getTree() {
-    chrome.bookmarks.getTree(function(results) {
-      assertNoLastError();
+    chrome.bookmarks.getTree(testFunction(function(results) {
       assertTrue(compareTrees(results, expected),
                  "getTree() result != expected");
       expected = results;
-      succeed();
-    });
+    }));
   },
-  
+
   function get() {
-    chrome.bookmarks.get("1", function(results) {
-      assertNoLastError();
+    chrome.bookmarks.get("1", testFunction(function(results) {
       assertTrue(compareNode(results[0], expected[0].children[0]));
-      succeed();
-    });
+    }));
   },
-  
+
   function getArray() {
-    chrome.bookmarks.get(["1", "2"], function(results) {
-      assertNoLastError();
+    chrome.bookmarks.get(["1", "2"], testFunction(function(results) {
       assertTrue(compareNode(results[0], expected[0].children[0]),
                  "get() result != expected");
       assertTrue(compareNode(results[1], expected[0].children[1]),
                  "get() result != expected");
-      succeed();
-    });
+    }));
   },
-  
+
   function getChildren() {
-    chrome.bookmarks.getChildren("0", function(results) {
-      assertNoLastError();
+    chrome.bookmarks.getChildren("0", testFunction(function(results) {
       assertTrue(compareNode(results[0], expected[0].children[0]),
                  "getChildren() result != expected");
       assertTrue(compareNode(results[1], expected[0].children[1]),
                  "getChildren() result != expected");
-      succeed();
-    });
+    }));
   },
-  
+
   function create() {
     var node = {parentId: "1", title:"google", url:"http://www.google.com/"};
-    chrome.bookmarks.create(node, function(results) {
-      assertNoLastError();
+    chrome.bookmarks.create(node, testFunction(function(results) {
       node.id = results.id;  // since we couldn't know this going in
       node.index = 0;
       assertTrue(compareNode(node, results),
                  "created node != source");
-      succeed();
-    });
+    }));
   },
 ];
 
 runNextTest();