Unicode Variation Selectors support in collectCandidateRuns

Source/platform/fonts/shaping/HarfBuzzShaperTest.cpp

Index: Source/platform/fonts/shaping/HarfBuzzShaperTest.cpp
diff --git a/Source/platform/fonts/shaping/HarfBuzzShaperTest.cpp b/Source/platform/fonts/shaping/HarfBuzzShaperTest.cpp
index b3f08af08a680b18ce0d07621737879e57545a7d..85904e992b4b3956ad781334b92f5c523c19ed16 100644
--- a/Source/platform/fonts/shaping/HarfBuzzShaperTest.cpp
+++ b/Source/platform/fonts/shaping/HarfBuzzShaperTest.cpp
@@ -67,6 +67,33 @@ TEST_F(HarfBuzzShaperTest, ResolveCandidateRunsLeadingCommon)
     ASSERT_EQ(script, HB_SCRIPT_LATIN);
 }
 
+TEST_F(HarfBuzzShaperTest, ResolveCandidateRunsUnicodeVariants)
+{
+    struct {
+        const char* name;
+        UChar string[4];
+        hb_script_t script;
+    } testlist[] = {
+        { "Standard Variants text style", { 0x30, 0xFE0E }, HB_SCRIPT_COMMON },
+        { "Standard Variants emoji style", { 0x203C, 0xFE0F }, HB_SCRIPT_COMMON },
+        { "Standard Variants of Ideograph", { 0x4FAE, 0xFE00 }, HB_SCRIPT_HAN },
+        { "Ideographic Variants", { 0x3402, 0xDB40, 0xDD00 }, HB_SCRIPT_HAN },
+        { "Not-defined Variants", { 0x41, 0xDB40, 0xDDEF }, HB_SCRIPT_LATIN },
+    };
+    for (auto& test : testlist) {
+        String str(test.string);
+        TextRun run(str);
+        HarfBuzzShaper shaper(font, run);
+        shaper.shape();
+        EXPECT_EQ(1u, shaper.numberOfRunsForTesting()) << test.name;
+        ASSERT_TRUE(shaper.runInfoForTesting(0, startIndex, numGlyphs, script)) << test.name;
+        EXPECT_EQ(0u, startIndex) << test.name;
+        // TODO(kojii): HarfBuzzFace does not support UVS yet and numGlyphs becomes 2
+        // EXPECT_EQ(1u, numGlyphs) << test.name;
+        EXPECT_EQ(test.script, script) << test.name;
+    }
+}
+
 TEST_F(HarfBuzzShaperTest, ResolveCandidateRunsDevanagariCommon)
 {
     UChar devanagariCommonString[] = { 0x915, 0x94d, 0x930, 0x28, 0x20, 0x29 };