Render Unicode control characters

third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.cpp

Index: third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
diff --git a/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.cpp b/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
index d13dd370db55c76c8bc431ec55280846e22229c7..56f39ca197c1c7ef0acf7dc1b8d8de724b402b81 100644
--- a/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
+++ b/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
@@ -32,6 +32,7 @@
 #include "platform/fonts/shaping/HarfBuzzShaper.h"
 
 #include "platform/Logging.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "platform/fonts/Font.h"
 #include "platform/fonts/FontFallbackIterator.h"
 #include "platform/fonts/GlyphBuffer.h"
@@ -98,12 +99,16 @@ static void normalizeCharacters(const TextRun& run, unsigned length, UChar* dest
         UChar32 character;
         U16_NEXT(source, position, length, character);
         // Don't normalize tabs as they are not treated as spaces for word-end.
-        if (run.normalizeSpace() && Character::isNormalizedCanvasSpaceCharacter(character))
+        if (run.normalizeSpace() && Character::isNormalizedCanvasSpaceCharacter(character)) {
             character = spaceCharacter;
-        else if (Character::treatAsSpace(character) && character != noBreakSpaceCharacter)
+        } else if (Character::treatAsSpace(character) && character != noBreakSpaceCharacter) {
             character = spaceCharacter;
-        else if (Character::treatAsZeroWidthSpaceInComplexScript(character))
+        } else if (!RuntimeEnabledFeatures::renderUnicodeControlCharactersEnabled()
+            && Character::legacyTreatAsZeroWidthSpaceInComplexScript(character)) {
             character = zeroWidthSpaceCharacter;
+        } else if (Character::treatAsZeroWidthSpaceInComplexScript(character)) {
+            character = zeroWidthSpaceCharacter;
+        }
 
         U16_APPEND(destination, *destinationLength, length, character, error);
         ASSERT_UNUSED(error, !error);