Implemented screen rotation animation experiment.

ash/rotator/screen_rotation_animation.cc

Index: ash/rotator/screen_rotation_animation.cc
diff --git a/ash/rotator/screen_rotation_animation.cc b/ash/rotator/screen_rotation_animation.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e7de7944e7b86eb683125879fb4b3a62860c73f4
--- /dev/null
+++ b/ash/rotator/screen_rotation_animation.cc
@@ -0,0 +1,70 @@
+// Copyright 2015 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/rotator/screen_rotation_animation.h"
+
+#include "base/time/time.h"
+#include "ui/compositor/layer.h"
+#include "ui/compositor/layer_animation_delegate.h"
+#include "ui/gfx/animation/tween.h"
+#include "ui/gfx/geometry/point.h"
+#include "ui/gfx/interpolated_transform.h"
+#include "ui/gfx/transform.h"
+
+namespace ash {
+
+ScreenRotationAnimation::ScreenRotationAnimation(ui::Layer* layer,
+    int start_degrees,
+    int end_degrees,
+    const gfx::Point3F& initial_scale,
+    const gfx::Point3F& target_scale,
+    gfx::Point pivot,
+    base::TimeDelta duration)
+    : ui::LayerAnimationElement(LayerAnimationElement::TRANSFORM |
+          LayerAnimationElement::OPACITY, duration),
+      tween_type_(gfx::Tween::LINEAR),
+      initial_opacity_(layer->opacity()),
+      target_opacity_(layer->GetTargetOpacity()) {
+  scoped_ptr<ui::InterpolatedTransform> scale(
+      new ui::InterpolatedTransformAboutPivot(
+          pivot,
+          new ui::InterpolatedScale(initial_scale, target_scale)));
+
+  scoped_ptr<ui::InterpolatedTransform> rotation(
+      new ui::InterpolatedTransformAboutPivot(
+          pivot,
+          new ui::InterpolatedRotation(start_degrees, end_degrees)));
+
+  // Use the target transform/bounds in case the layer is already animating.
+  gfx::Transform current_transform = layer->GetTargetTransform();
+  interpolated_transform_.reset(
+      new ui::InterpolatedConstantTransform(current_transform));
+  scale->SetChild(rotation.release());
+  interpolated_transform_->SetChild(scale.release());
+}
+
+ScreenRotationAnimation::~ScreenRotationAnimation() {
+}
+
+void ScreenRotationAnimation::OnStart(ui::LayerAnimationDelegate* delegate) {
+}
+
+bool ScreenRotationAnimation::OnProgress(double t,
+                                         ui::LayerAnimationDelegate* delegate) {
+  double tweened_t = gfx::Tween::CalculateValue(tween_type_, t);
+  delegate->SetTransformFromAnimation(interpolated_transform_->Interpolate(
+      tweened_t));
+  delegate->SetOpacityFromAnimation(gfx::Tween::FloatValueBetween(tweened_t,
+      initial_opacity_, target_opacity_));
+  return true;
+}
+
+void ScreenRotationAnimation::OnGetTarget(TargetValue* target) const {
+  target->transform = interpolated_transform_->Interpolate(1.0);
+}
+
+void ScreenRotationAnimation::OnAbort(ui::LayerAnimationDelegate* delegate) {
+}
+
+}  // namespace ash