Rename AnimationPlayer to Animation in cc and all its clients

This patch updates the name cc::AnimationPlayer to cc::Animation so that
it will be consistent with the blink::Animation. It's a follow-up patch
of https://chromium-review.googlesource.com/c/chromium/src/+/906830.

Other clients of cc::Animation (vr, ui) have been updated accordingly.

Bug: 807667
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_vr;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: If80affe7bedf46ae8f0356a6fa8a89e2f1d81973
Reviewed-on: https://chromium-review.googlesource.com/926901
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Reviewed-by: Majid Valipour <majidvp@chromium.org>
Reviewed-by: Ian Vollick <vollick@chromium.org>
Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#538327}

cc/BUILD.gn

@@ -710,7 +710,7 @@ cc_test("cc_unittests") {
     "animation/scroll_offset_animation_curve_unittest.cc",
     "animation/scroll_timeline_unittest.cc",
     "animation/transform_operations_unittest.cc",
-    "animation/worklet_animation_player_unittest.cc",
+    "animation/worklet_animation_unittest.cc",
 
     # Setup.
     "test/cc_test_suite.cc",

cc/animation/BUILD.gn

@@ -7,6 +7,8 @@ import("//cc/cc.gni")
 cc_component("animation") {
   output_name = "cc_animation"
   sources = [
+    "animation.cc",
+    "animation.h",
     "animation_curve.cc",
     "animation_curve.h",
     "animation_delegate.h",
@@ -17,8 +19,6 @@ cc_component("animation") {
     "animation_host.h",
     "animation_id_provider.cc",
     "animation_id_provider.h",
-    "animation_player.cc",
-    "animation_player.h",
     "animation_target.h",
     "animation_timeline.cc",
     "animation_timeline.h",
@@ -38,16 +38,16 @@ cc_component("animation") {
     "scroll_offset_animations_impl.h",
     "scroll_timeline.cc",
     "scroll_timeline.h",
-    "single_keyframe_effect_animation_player.cc",
-    "single_keyframe_effect_animation_player.h",
+    "single_keyframe_effect_animation.cc",
+    "single_keyframe_effect_animation.h",
     "timing_function.cc",
     "timing_function.h",
     "transform_operation.cc",
     "transform_operation.h",
     "transform_operations.cc",
     "transform_operations.h",
-    "worklet_animation_player.cc",
-    "worklet_animation_player.h",
+    "worklet_animation.cc",
+    "worklet_animation.h",
   ]
 
   defines = [ "CC_ANIMATION_IMPLEMENTATION=1" ]

cc/animation/README.md

@@ -40,23 +40,23 @@ sent when all animations in the group have finished.
 Animations are grouped together based on their
 [animation target](https://codesearch.chromium.org/chromium/src/cc/animation/animation_target.h)
 (the entity whose property is being animated) and each such group is owned by an
-[animation player](https://codesearch.chromium.org/chromium/src/cc/animation/animation_player.h).
-Note that there may be multiple animation players with the same target (each
+[animation](https://codesearch.chromium.org/chromium/src/cc/animation/animation.h).
+Note that there may be multiple animations with the same target (each
 with a set of KeyframeModels for that target); the
 [ElementAnimations](https://codesearch.chromium.org/chromium/src/cc/animation/element_animations.h)
-class wraps the multiple animation players and has a 1:1 relationship with
+class wraps the multiple animations and has a 1:1 relationship with
 target entities.
 
-`TODO(smcgruer): Why are ElementAnimations and AnimationPlayers separate?`
+`TODO(smcgruer): Why are ElementAnimations and Animations separate?`
 
 In order to play an animation, input time values must be provided to the
 animation curve and output values fed back into the animating entity. This is
 called 'ticking' an animation and is the responsibility of the
 [animation host](https://codesearch.chromium.org/chromium/src/cc/animation/animation_host.h).
-The animation host has a list of currently ticking players (i.e. those that have
+The animation host has a list of currently ticking animations (i.e. those that have
 any non-deleted animations), which it iterates through whenever it receives a
 tick call from the client (along with a corresponding input time).  The
-animation players then call into their non-deleted animations, retrieving the
+animations then call into their non-deleted animations, retrieving the
 value from the animation curve.  As they are computed, output values are sent to
 the target which is responsible for passing them to the client entity that is
 being animated.
@@ -93,7 +93,7 @@ cc/animation has a concept of an
 [animation timeline](https://codesearch.chromium.org/chromium/src/cc/animation/animation_timeline.h).
 This should not be confused with the identically named Blink concept. In
 cc/animation, animation timelines are an implementation detail - they hold the
-animation players and are responsible for syncing them to the impl thread (see
+animations and are responsible for syncing them to the impl thread (see
 below), but do not participate in the ticking process in any way.
 
 ### Main/Impl Threads