Stop combining text runs which are connected by 'COMMON' blocks.

ui/gfx/render_text.h

Index: ui/gfx/render_text.h
diff --git a/ui/gfx/render_text.h b/ui/gfx/render_text.h
index 87a66f382958712da9622ae0ce3478bec2b51ece..405dcd66b300723acd04f5a60e542a0fb3057a94 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -637,6 +637,10 @@ class GFX_EXPORT RenderText {
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_SufficientWidth);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_Newline);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_WordWrapBehavior);
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_LineBreakerBehavior);
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest,
+                           Multiline_SurrogatePairsOrCombiningChars);
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_ZeroWidthChars);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, NewlineWithoutMultilineFlag);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, GlyphBounds);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_GlyphBounds);