Stopped using CreateFunctor in DownloadUIController_HistoryDownload.

Switching from testing::CreateFunctor to a C++ lambda is
slightly easier to understand, but allows the deletion of
an upcoming CL to delete gmock_mutant.h.

Bug: 1007833, 806952
Change-Id: Ib210a0c92090ca330f99b695a3256c981f7f14e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1887661Reviewed-by: Xing Liu <xingliu@chromium.org>
Commit-Queue: Chris Mumford <cmumford@google.com>
Cr-Commit-Position: refs/heads/master@{#710424}

chrome/browser/download/download_ui_controller_unittest.cc

@@ -27,7 +27,6 @@
 #include "content/public/test/mock_download_manager.h"
 #include "content/public/test/navigation_simulator.h"
 #include "testing/gmock/include/gmock/gmock.h"
-#include "testing/gmock_mutant.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using content::MockDownloadManager;
@@ -36,7 +35,6 @@ using history::HistoryService;
 using testing::_;
 using testing::AnyNumber;
 using testing::Assign;
-using testing::CreateFunctor;
 using testing::Return;
 using testing::ReturnRef;
 using testing::ReturnRefOfCopy;
@@ -360,15 +358,17 @@ TEST_F(DownloadUIControllerTest, DownloadUIController_HistoryDownload) {
     // is called, we need to first invoke the OnDownloadCreated callback for
     // DownloadHistory before returning the DownloadItem since that's the
     // sequence of events expected by DownloadHistory.
-    base::Closure history_on_created_callback =
-        base::Bind(&content::DownloadManager::Observer::OnDownloadCreated,
-                   base::Unretained(download_history_manager_observer()),
-                   manager(),
-                   item.get());
+    content::DownloadManager::Observer* observer =
+        download_history_manager_observer();
+    MockDownloadManager* download_manager = manager();
+    MockDownloadItem* download_item = item.get();
     EXPECT_CALL(*manager(), MockCreateDownloadItem(_))
-        .WillOnce(testing::DoAll(testing::InvokeWithoutArgs(CreateFunctor(
-                                     history_on_created_callback)),
-                                 Return(item.get())));
+        .WillOnce(testing::DoAll(
+            testing::InvokeWithoutArgs(
+                [observer, download_manager, download_item]() {
+                  observer->OnDownloadCreated(download_manager, download_item);
+                }),
+            Return(item.get())));
     EXPECT_CALL(mock_function, Call());
 
     std::move(*history_query_callback()).Run(std::move(history_downloads));