Fix EditingStyle::mergeStyle()'s handling of custom properties

third_party/WebKit/Source/core/editing/EditingStyleTest.cpp

Index: third_party/WebKit/Source/core/editing/EditingStyleTest.cpp
diff --git a/third_party/WebKit/Source/core/editing/EditingStyleTest.cpp b/third_party/WebKit/Source/core/editing/EditingStyleTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..1e08e2e99346c3423c61f829921887c4ce545bfa
--- /dev/null
+++ b/third_party/WebKit/Source/core/editing/EditingStyleTest.cpp
@@ -0,0 +1,41 @@
+// Copyright 2016 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 "core/editing/EditingStyle.h"
+
+#include "core/css/StylePropertySet.h"
+#include "core/dom/Document.h"
+#include "core/editing/EditingTestBase.h"
+#include "core/html/HTMLBodyElement.h"
+#include "core/html/HTMLDivElement.h"
+#include "core/html/HTMLHeadElement.h"
+#include "core/html/HTMLHtmlElement.h"
+
+namespace blink {
+
+class EditingStyleTest : public EditingTestBase {
+};
+
+TEST_F(EditingStyleTest, mergeInlineStyleOfElement)
+{
+    setBodyContent(
+        "<span id=s1 style='--A:var(---B)'>1</span>"
+        "<span id=s2 style='float:var(--C)'>2</span>");
+    updateAllLifecyclePhases();
+
+    EditingStyle* editingStyle = EditingStyle::create(
+        toHTMLElement(document().getElementById("s2")));
+    editingStyle->mergeInlineStyleOfElement(
+        toHTMLElement(document().getElementById("s1")),
+        EditingStyle::OverrideValues);
+
+    EXPECT_FALSE(editingStyle->style()->hasProperty(CSSPropertyFloat))
+        << "Don't merge a property with unresolved value";
+    EXPECT_EQ(
+        "var(---B)",
+        editingStyle->style()->getPropertyValue(AtomicString("--A")))
+        << "Keep unresolved value on merging style";
+}
+
+} // namespace blink