Adding backgroundColor to WebCompositionUnderline and using it for InlineTextBox drawing.

Source/core/editing/CompositionUnderlineVisitor.cpp

Index: Source/core/editing/CompositionUnderlineVisitor.cpp
diff --git a/Source/core/editing/CompositionUnderlineVisitor.cpp b/Source/core/editing/CompositionUnderlineVisitor.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..fcd8e65779c99223bad0bbc8a0cdda26348cd7e7
--- /dev/null
+++ b/Source/core/editing/CompositionUnderlineVisitor.cpp
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2014 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "core/editing/CompositionUnderlineVisitor.h"
+
+namespace WebCore {
+
+bool CompositionUnderlineVisitor::next(const CompositionUnderline** underlineOut)
+{
+    size_t numUnderlines = m_underlines.size();
+    while (m_nextIndex < numUnderlines) {
+        const CompositionUnderline& underline = m_underlines[m_nextIndex];
+        ++m_nextIndex;
+
+        if (underline.endOffset <= m_indexLo) {
+            // underline is completely before interval. This may be an underline that appear
+            // before the first run, or may be a underline within current run that got
+            // skipped due to truncation.
+        } else if (underline.startOffset <= m_indexHi) {
+            // underline intersects current run. Process it.
+            *underlineOut = &underline;
+            return true;
+        } else {
+            // underline is completely after this run, bail. A later run will process it.
+            break;
+        }
+    }
+    return false;
+}
+
+} // namespace WebCore