Adding backgroundColor to WebCompositionUnderline and using it for InlineTextBox drawing.

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 51c45460b378c2f15239fceba6f3b17969307127..52ef8c571783c493f37a82e25ffb747565b89763 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -2340,7 +2340,7 @@ WebVector<WebCompositionUnderline> WebViewImpl::compositionUnderlines() const
     WebVector<WebCompositionUnderline> results(underlines.size());
     for (size_t index = 0; index < underlines.size(); ++index) {
         CompositionUnderline underline = underlines[index];
-        results[index] = WebCompositionUnderline(underline.startOffset, underline.endOffset, static_cast<WebColor>(underline.color.rgb()), underline.thick);
+        results[index] = WebCompositionUnderline(underline.startOffset, underline.endOffset, static_cast<WebColor>(underline.color.rgb()), underline.thick, static_cast<WebColor>(underline.backgroundColor.rgb()));
     }
     return results;
 }