Mozart: Add hit testing interfaces.

mojo/services/gfx/composition/cpp/formatting.h

Index: mojo/services/gfx/composition/cpp/formatting.h
diff --git a/mojo/services/gfx/composition/cpp/formatting.h b/mojo/services/gfx/composition/cpp/formatting.h
index 0f4df77da69558133b0d7b6716e1552a130600b3..f7a1eb798b80218d6fd34e7d4212f8712df0d354 100644
--- a/mojo/services/gfx/composition/cpp/formatting.h
+++ b/mojo/services/gfx/composition/cpp/formatting.h
@@ -57,6 +57,18 @@ std::ostream& operator<<(std::ostream& os,
 std::ostream& operator<<(std::ostream& os,
                          const mojo::gfx::composition::FrameInfo& value);
 
+std::ostream& operator<<(std::ostream& os,
+                         const mojo::gfx::composition::HitTestBehavior& value);
+std::ostream& operator<<(
+    std::ostream& os,
+    const mojo::gfx::composition::HitTestBehavior::Visibility* value);
+std::ostream& operator<<(std::ostream& os,
+                         const mojo::gfx::composition::HitTestResult& value);
+std::ostream& operator<<(std::ostream& os,
+                         const mojo::gfx::composition::SceneHit& value);
+std::ostream& operator<<(std::ostream& os,
+                         const mojo::gfx::composition::NodeHit& value);
+
 }  // namespace composition
 }  // namespace gfx
 }  // namespace mojo