Refactor LayerAnimationInfo into its own class.

This addresses a TODO from a preview CL. No functional changes.

Change-Id: I21e99b55f285475d8321fea260751be3f18d811b
Reviewed-on: https://chromium-review.googlesource.com/1135519Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Katie Dektar <katie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575035}

ash/BUILD.gn

@@ -81,6 +81,8 @@ component("ash") {
     "accessibility/focus_ring_layer.h",
     "accessibility/key_accessibility_enabler.cc",
     "accessibility/key_accessibility_enabler.h",
+    "accessibility/layer_animation_info.cc",
+    "accessibility/layer_animation_info.h",
     "accessibility/spoken_feedback_enabler.cc",
     "accessibility/spoken_feedback_enabler.h",
     "accessibility/touch_accessibility_enabler.cc",

ash/accessibility/accessibility_focus_ring_controller.cc

@@ -17,6 +17,7 @@
 #include "ash/accessibility/accessibility_focus_ring_layer.h"
 #include "ash/accessibility/accessibility_highlight_layer.h"
 #include "ash/accessibility/focus_ring_layer.h"
+#include "ash/accessibility/layer_animation_info.h"
 #include "base/logging.h"
 
 namespace ash {
@@ -217,8 +218,7 @@ void AccessibilityFocusRingController::AnimateCursorRing(
     base::TimeTicks timestamp) {
   CHECK(cursor_layer_);
 
-  AccessibilityFocusRingGroup::ComputeOpacity(&cursor_animation_info_,
-                                              timestamp);
+  ComputeOpacity(&cursor_animation_info_, timestamp);
   if (cursor_animation_info_.opacity == 0.0) {
     cursor_layer_.reset();
     return;
@@ -230,10 +230,7 @@ void AccessibilityFocusRingController::AnimateCaretRing(
     base::TimeTicks timestamp) {
   CHECK(caret_layer_);
 
-  // TODO(katie): Move ComputeOpacity into a separate source file, as it is used
-  // by more than just AccessibilityFocusRingGroup.
-  AccessibilityFocusRingGroup::ComputeOpacity(&caret_animation_info_,
-                                              timestamp);
+  ComputeOpacity(&caret_animation_info_, timestamp);
   if (caret_animation_info_.opacity == 0.0) {
     caret_layer_.reset();
     return;

ash/accessibility/accessibility_focus_ring_controller.h

@@ -11,6 +11,7 @@
 #include "ash/accessibility/accessibility_focus_ring.h"
 #include "ash/accessibility/accessibility_focus_ring_group.h"
 #include "ash/accessibility/accessibility_layer.h"
+#include "ash/accessibility/layer_animation_info.h"
 #include "ash/ash_export.h"
 #include "ash/public/interfaces/accessibility_focus_ring_controller.mojom.h"
 #include "base/bind.h"

ash/accessibility/accessibility_focus_ring_group.cc

@@ -10,6 +10,7 @@
 #include "ash/accessibility/accessibility_focus_ring.h"
 #include "ash/accessibility/accessibility_focus_ring_layer.h"
 #include "ash/accessibility/accessibility_layer.h"
+#include "ash/accessibility/layer_animation_info.h"
 #include "ash/public/interfaces/accessibility_focus_ring_controller.mojom.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/geometry/rect.h"
@@ -138,7 +139,7 @@ void AccessibilityFocusRingGroup::AnimateFocusRings(base::TimeTicks timestamp) {
     focus_layers_[0]->Set(AccessibilityFocusRing::Interpolate(
         previous_focus_rings_[0], focus_rings_[0], fraction));
   } else {
-    ComputeOpacity(&(focus_animation_info_), timestamp);
+    ash::ComputeOpacity(&(focus_animation_info_), timestamp);
     for (size_t i = 0; i < focus_layers_.size(); ++i)
       focus_layers_[i]->SetOpacity(focus_animation_info_.opacity);
   }
@@ -170,39 +171,6 @@ void AccessibilityFocusRingGroup::ClearFocusRects(
   UpdateFocusRingsFromFocusRects(delegate);
 }
 
-void AccessibilityFocusRingGroup::ComputeOpacity(
-    LayerAnimationInfo* animation_info,
-    base::TimeTicks timestamp) {
-  // It's quite possible for the first 1 or 2 animation frames to be
-  // for a timestamp that's earlier than the time we received the
-  // mouse movement, so we just treat those as a delta of zero.
-  if (timestamp < animation_info->start_time)
-    timestamp = animation_info->start_time;
-
-  base::TimeDelta start_delta = timestamp - animation_info->start_time;
-  base::TimeDelta change_delta = timestamp - animation_info->change_time;
-  base::TimeDelta fade_in_time = animation_info->fade_in_time;
-  base::TimeDelta fade_out_time = animation_info->fade_out_time;
-
-  if (change_delta > fade_in_time + fade_out_time) {
-    animation_info->opacity = 0.0;
-    return;
-  }
-
-  float opacity;
-  if (start_delta < fade_in_time) {
-    opacity = start_delta.InSecondsF() / fade_in_time.InSecondsF();
-  } else {
-    opacity = 1.0 - (change_delta.InSecondsF() /
-                     (fade_in_time + fade_out_time).InSecondsF());
-  }
-
-  // Layer::SetOpacity will throw an error if we're not within 0...1.
-  opacity = std::min(std::max(opacity, 0.0f), 1.0f);
-
-  animation_info->opacity = opacity;
-}
-
 int AccessibilityFocusRingGroup::GetMargin() const {
   return kAccessibilityFocusRingMargin;
 }

ash/accessibility/accessibility_focus_ring_group.h

@@ -11,6 +11,7 @@
 #include "ash/accessibility/accessibility_focus_ring.h"
 #include "ash/accessibility/accessibility_focus_ring_layer.h"
 #include "ash/accessibility/accessibility_layer.h"
+#include "ash/accessibility/layer_animation_info.h"
 #include "ash/ash_export.h"
 #include "ash/public/interfaces/accessibility_focus_ring_controller.mojom.h"
 #include "third_party/skia/include/core/SkColor.h"
@@ -18,17 +19,6 @@
 
 namespace ash {
 
-// TODO(katie): Move into a separate source file as it can be used by more than
-// just AccessibilityFocusRingGroup.
-struct LayerAnimationInfo {
-  base::TimeTicks start_time;
-  base::TimeTicks change_time;
-  base::TimeDelta fade_in_time;
-  base::TimeDelta fade_out_time;
-  float opacity = 0;
-  bool smooth = false;
-};
-
 // AccessibilityFocusRingGroup handles tracking all the elements of a group of
 // focus rings, including their positions, colors, and animation behavior.
 // In general each extension or caller will have only one

ash/accessibility/layer_animation_info.cc

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ash/accessibility/layer_animation_info.h"
+
+namespace ash {
+
+void ComputeOpacity(LayerAnimationInfo* animation_info,
+                    base::TimeTicks timestamp) {
+  // It's quite possible for the first 1 or 2 animation frames to be
+  // for a timestamp that's earlier than the time we received the
+  // mouse movement, so we just treat those as a delta of zero.
+  if (timestamp < animation_info->start_time)
+    timestamp = animation_info->start_time;
+
+  base::TimeDelta start_delta = timestamp - animation_info->start_time;
+  base::TimeDelta change_delta = timestamp - animation_info->change_time;
+  base::TimeDelta fade_in_time = animation_info->fade_in_time;
+  base::TimeDelta fade_out_time = animation_info->fade_out_time;
+
+  if (change_delta > fade_in_time + fade_out_time) {
+    animation_info->opacity = 0.0;
+    return;
+  }
+
+  float opacity;
+  if (start_delta < fade_in_time) {
+    opacity = start_delta.InSecondsF() / fade_in_time.InSecondsF();
+  } else {
+    opacity = 1.0 - (change_delta.InSecondsF() /
+                     (fade_in_time + fade_out_time).InSecondsF());
+  }
+
+  // Layer::SetOpacity will throw an error if we're not within 0...1.
+  opacity = std::min(std::max(opacity, 0.0f), 1.0f);
+
+  animation_info->opacity = opacity;
+}
+
+}  // namespace ash
\ No newline at end of file

ash/accessibility/layer_animation_info.h

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ASH_ACCESSIBILITY_LAYER_ANIMATION_INFO_H_
+#define ASH_ACCESSIBILITY_LAYER_ANIMATION_INFO_H_
+
+#include "base/time/time.h"
+
+namespace ash {
+
+struct LayerAnimationInfo {
+  base::TimeTicks start_time;
+  base::TimeTicks change_time;
+  base::TimeDelta fade_in_time;
+  base::TimeDelta fade_out_time;
+  float opacity = 0;
+  bool smooth = false;
+};
+
+void ComputeOpacity(LayerAnimationInfo* animation_info,
+                    base::TimeTicks timestamp);
+
+}  // namespace ash
+
+#endif  // ASH_ACCESSIBILITY_LAYER_ANIMATION_INFO_H_