Using ScopedTempDir as the download directory used by the DownloadViaPost test.

chrome/browser/extensions/api/extension_action/browser_action_apitest.cc

Index: chrome/browser/extensions/api/extension_action/browser_action_apitest.cc
diff --git a/chrome/browser/extensions/api/extension_action/browser_action_apitest.cc b/chrome/browser/extensions/api/extension_action/browser_action_apitest.cc
index 9cbfe71b08382da2e372b61646a7c3d1b3ec9721..876abcc72a4f205de1a94ac1b907498804f73956 100644
--- a/chrome/browser/extensions/api/extension_action/browser_action_apitest.cc
+++ b/chrome/browser/extensions/api/extension_action/browser_action_apitest.cc
@@ -4,6 +4,9 @@
 
 #include <stdint.h>
 
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/files/scoped_temp_dir.h"
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "chrome/browser/extensions/api/extension_action/extension_action_api.h"
@@ -23,8 +26,10 @@
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/extensions/extension_process_policy.h"
+#include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/base/ui_test_utils.h"
+#include "components/prefs/pref_service.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_frame_host.h"
@@ -64,6 +69,18 @@ void ExecuteExtensionAction(Browser* browser, const Extension* extension) {
       ->RunAction(extension, true);
 }
 
+std::unique_ptr<base::ScopedTempDir> CreateAndSetDownloadsDirectory(
+    PrefService* pref_service) {
+  std::unique_ptr<base::ScopedTempDir> dir(new base::ScopedTempDir);
+
+  if (!dir->CreateUniqueTempDir())
+    return nullptr;
+
+  pref_service->SetFilePath(prefs::kDownloadDefaultDirectory, dir->GetPath());
+  pref_service->SetFilePath(prefs::kSaveFileDefaultDirectory, dir->GetPath());
+  return dir;
+}
+
 // An ImageSkia source that will do nothing (i.e., have a blank skia). We need
 // this because we need a blank canvas at a certain size, and that can't be done
 // by just using a null ImageSkia.
@@ -991,16 +1008,15 @@ IN_PROC_BROWSER_TEST_F(NavigatingExtensionPopupBrowserTest,
 // GET should automagically start working for downloads.
 // TODO(lukasza): https://crbug.com/650694: Add a "Get" flavour of the test once
 // the download works both for GET and POST requests.
-
-// Disabled on Windows and Mac. See http://crbug.com/653856.
-#if defined(OS_WIN) || defined(OS_MACOSX)
-#define MAYBE_DownloadViaPost DISABLED_DownloadViaPost
-#else
-#define MAYBE_DownloadViaPost DownloadViaPost
-#endif
-
-IN_PROC_BROWSER_TEST_F(NavigatingExtensionPopupBrowserTest,
-                       MAYBE_DownloadViaPost) {
+IN_PROC_BROWSER_TEST_F(NavigatingExtensionPopupBrowserTest, DownloadViaPost) {
+  // Override the default downloads directory, so that the test can cleanup
+  // after itself.  This section is based on CreateAndSetDownloadsDirectory
+  // method defined in a few other source files with tests.
+  std::unique_ptr<base::ScopedTempDir> downloads_directory =
+      CreateAndSetDownloadsDirectory(browser()->profile()->GetPrefs());
+  ASSERT_TRUE(downloads_directory);
+
+  // Setup monitoring of the downloads.
   content::DownloadTestObserverTerminal downloads_observer(
       content::BrowserContext::GetDownloadManager(browser()->profile()),
       1,  // == wait_count (only waiting for "download-test3.gif").
@@ -1018,6 +1034,8 @@ IN_PROC_BROWSER_TEST_F(NavigatingExtensionPopupBrowserTest,
   EXPECT_EQ(0u, downloads_observer.NumDangerousDownloadsSeen());
   EXPECT_EQ(1u, downloads_observer.NumDownloadsSeenInState(
                     content::DownloadItem::COMPLETE));
+  EXPECT_TRUE(base::PathExists(downloads_directory->GetPath().AppendASCII(
+      "download-test3-attachment.gif")));
 
   // The test verification below is applicable only to scenarios where the
   // download shelf is supported - on ChromeOS, instead of the download shelf,