Make LocalCaretRectTest also compare LayoutObject

Change-Id: If483a1ac2b02eabfc9ff7d9f3a5a9619b505d5b0
Reviewed-on: https://chromium-review.googlesource.com/875315
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530616}

third_party/WebKit/Source/core/editing/LocalCaretRect.h

@@ -35,6 +35,10 @@ LocalCaretRectOfPosition(const PositionInFlatTreeWithAffinity&);
 
 LocalCaretRect LocalSelectionRectOfPosition(const PositionWithAffinity&);
 
+// Exposed to tests only. Implemented in LocalCaretRectTest.cpp.
+bool operator==(const LocalCaretRect&, const LocalCaretRect&);
+std::ostream& operator<<(std::ostream&, const LocalCaretRect&);
+
 }  // namespace blink
 
 #endif  // LocalCaretRect_h