CC Animation: Use std::bitset to update animation state.

cc/animation/target_property.h

Index: cc/animation/target_property.h
diff --git a/cc/animation/target_property.h b/cc/animation/target_property.h
index 4ba1e1daf7db0bf4c39d2874996f255bc3183655..632e826a00ca66a2bd81c14d7259c916850c50e3 100644
--- a/cc/animation/target_property.h
+++ b/cc/animation/target_property.h
@@ -5,6 +5,8 @@
 #ifndef CC_ANIMATION_TARGET_PROPERTY_H_
 #define CC_ANIMATION_TARGET_PROPERTY_H_
 
+#include <bitset>
+
 namespace cc {
 
 namespace TargetProperty {
@@ -24,6 +26,9 @@ const char* GetName(TargetProperty::Type property);
 
 }  // namespace TargetProperty
 
+// A set of target properties. TargetProperty must be 0-based enum.
+using TargetProperties = std::bitset<TargetProperty::LAST_TARGET_PROPERTY + 1>;
+
 }  // namespace cc
 
 #endif  // CC_ANIMATION_TARGET_PROPERTY_H_