abmient: Replace middle dot to bullet

The middle dot symbol is very small. Replace it with a larger symbol,
bullet.

Bug: b/173754433
Test: manual && modified test
Change-Id: Ie7cd84a91b7d7374dff6087954f1f7be9426a62a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2577605
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#834305}

ash/ambient/ui/media_string_view.cc

@@ -99,7 +99,7 @@ class FadeoutLayerDelegate : public ui::LayerDelegate {
 };
 
 // Typography.
-constexpr char kMiddleDotSeparator[] = " \u00B7 ";
+constexpr char kMiddleDotSeparator[] = " \u2022 ";
 
 constexpr int kMusicNoteIconSizeDip = 20;
 

ash/ambient/ui/media_string_view_unittest.cc

@@ -48,7 +48,7 @@ TEST_F(MediaStringViewTest, ShowMediaTitleAndArtist) {
 
   SimulateMediaMetadataChanged(metadata);
 
-  const base::string16 expected_text = base::UTF8ToUTF16("title \u00B7 artist");
+  const base::string16 expected_text = base::UTF8ToUTF16("title \u2022 artist");
   EXPECT_EQ(GetMediaStringViewTextLabel()->GetText(), expected_text);
 }