Don't clip out nodes if the clip is an empty rectangle

http://b/issue?id=1945476
diff --git a/WebKit/android/nav/CacheBuilder.cpp b/WebKit/android/nav/CacheBuilder.cpp
index ac24668..207de0c 100644
--- a/WebKit/android/nav/CacheBuilder.cpp
+++ b/WebKit/android/nav/CacheBuilder.cpp
@@ -1180,7 +1180,7 @@
                 clip.intersect(parentClip);
             hasClip = true;
         }
-        if (hasClip && cachedNode.clip(clip) == false) {
+        if (hasClip && !clip.isEmpty() && cachedNode.clip(clip) == false) {
             cachedNode.setBounds(clip);
             cachedNode.cursorRings().append(clip);
             isUnclipped = true;