Introduce WebRange::isEmpty.

third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp

Index: third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp b/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
index 65fcf0b8217be3baae17a27b6a4ff54c4b9ae359..bffe47f3aab7b7c793923b77cf05a22910d8448c 100644
--- a/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
+++ b/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
@@ -876,10 +876,7 @@ void WebFrameWidgetImpl::didLosePointerLock()
 bool WebFrameWidgetImpl::getCompositionCharacterBounds(WebVector<WebRect>& bounds)
 {
     WebRange range = compositionRange();
-    if (range.isNull())
-        return false;
-
-    if (range.length() == 0)
+    if (range.isEmpty())
         return false;
 
     LocalFrame* frame = focusedLocalFrameInWidget();