PlatformFontMac: Use a default NSFont when an invalid font is passed.

ui/gfx/render_text_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/render_text.h"
 
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 4514 matching lines @@
   }
 
   // Test complete bounds.
   render_text->SelectAll(false);
   EXPECT_EQ(expected_total_bounds, GetSelectionBoundsUnion());
 }
 
 // Tests that RenderText doesn't crash even if it's passed an invalid font. Test
 // for crbug.com/668058.
 TEST_P(RenderTextTest, InvalidFont) {
-// TODO(crbug.com/699820): This crashes with RenderTextHarfBuzz on Mac.
-#if defined(OS_MACOSX)
-  if (GetParam() == RENDER_TEXT_HARFBUZZ)
-    return;
-#endif
   const std::string font_name = "invalid_font";
   const int kFontSize = 13;
   RenderText* render_text = GetRenderText();
   render_text->SetFontList(FontList(Font(font_name, kFontSize)));
   render_text->SetText(ASCIIToUTF16("abc"));
 
   DrawVisualText();
 }
 
 TEST_P(RenderTextHarfBuzzTest, LinesInvalidationOnElideBehaviorChange) {
@@ skipping 120 matching lines @@
                         ::testing::Values(RENDER_TEXT_HARFBUZZ),
                         PrintRenderTextBackend());
 #endif
 
 INSTANTIATE_TEST_CASE_P(,
                         RenderTextHarfBuzzTest,
                         ::testing::Values(RENDER_TEXT_HARFBUZZ),
                         PrintRenderTextBackend());
 
 }  // namespace gfx