polychrome: disable modal animations in PrintPreviewDialogControllerBrowserTest

These tests don't work when using a Mac printing dialog with MacViews, because
the modal closure animation makes window closure very asynchronous. Disable
it altogether in this set of tests.

Bug: 817408
Change-Id: Idb1bd814e9248e0cbd8d07e3426084c72db06d65
Reviewed-on: https://chromium-review.googlesource.com/975521Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545089}

chrome/browser/printing/print_preview_dialog_controller_browsertest.cc

@@ -7,6 +7,7 @@
 #include <memory>
 
 #include "base/bind_helpers.h"
+#include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/location.h"
 #include "base/macros.h"
@@ -37,6 +38,7 @@
 #include "content/public/test/browser_test_utils.h"
 #include "ipc/ipc_message_macros.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/base/ui_base_switches.h"
 #include "url/gurl.h"
 #include "url/origin.h"
 
@@ -182,6 +184,11 @@ class PrintPreviewDialogControllerBrowserTest : public InProcessBrowserTest {
 
  private:
   void SetUpOnMainThread() override {
+#if defined(OS_MACOSX)
+    base::CommandLine::ForCurrentProcess()->AppendSwitch(
+        switches::kDisableModalAnimations);
+#endif
+
     WebContents* first_tab =
         browser()->tab_strip_model()->GetActiveWebContents();
     ASSERT_TRUE(first_tab);