CC Animation: Remove Observers and Observations in namings.

cc/animation/animation.h

Index: cc/animation/animation.h
diff --git a/cc/animation/animation.h b/cc/animation/animation.h
index fff74fad900f7a46f24b757e87d4896c895c7775..ba0b5171d0667c7715741f1db29ea762e3f31c4c 100644
--- a/cc/animation/animation.h
+++ b/cc/animation/animation.h
@@ -159,15 +159,15 @@ class CC_EXPORT Animation {
   void set_is_impl_only(bool is_impl_only) { is_impl_only_ = is_impl_only; }
   bool is_impl_only() const { return is_impl_only_; }
 
-  void set_affects_active_observers(bool affects_active_observers) {
-    affects_active_observers_ = affects_active_observers;
+  void set_affects_active_elements(bool affects_active_elements) {
+    affects_active_elements_ = affects_active_elements;
   }
-  bool affects_active_observers() const { return affects_active_observers_; }
+  bool affects_active_elements() const { return affects_active_elements_; }
 
-  void set_affects_pending_observers(bool affects_pending_observers) {
-    affects_pending_observers_ = affects_pending_observers;
+  void set_affects_pending_elements(bool affects_pending_elements) {
+    affects_pending_elements_ = affects_pending_elements;
   }
-  bool affects_pending_observers() const { return affects_pending_observers_; }
+  bool affects_pending_elements() const { return affects_pending_elements_; }
 
  private:
   Animation(std::unique_ptr<AnimationCurve> curve,
@@ -230,18 +230,18 @@ class CC_EXPORT Animation {
   bool is_impl_only_;
 
   // When pushed from a main-thread controller to a compositor-thread
-  // controller, an animation will initially only affect pending observers
+  // controller, an animation will initially only affect pending elements
   // (corresponding to layers in the pending tree). Animations that only
-  // affect pending observers are able to reach the STARTING state and tick
-  // pending observers, but cannot proceed any further and do not tick active
-  // observers. After activation, such animations affect both kinds of observers
+  // affect pending elements are able to reach the STARTING state and tick
+  // pending elements, but cannot proceed any further and do not tick active
+  // elements. After activation, such animations affect both kinds of elements
   // and are able to proceed past the STARTING state. When the removal of
   // an animation is pushed from a main-thread controller to a
   // compositor-thread controller, this initially only makes the animation
-  // stop affecting pending observers. After activation, such animations no
-  // longer affect any observers, and are deleted.
-  bool affects_active_observers_;
-  bool affects_pending_observers_;
+  // stop affecting pending elements. After activation, such animations no
+  // longer affect any elements, and are deleted.
+  bool affects_active_elements_;
+  bool affects_pending_elements_;
 
   DISALLOW_COPY_AND_ASSIGN(Animation);
 };