Refactor GestureNavigation to eliminate code redundancy

content/browser/web_contents/aura/overscroll_window_animation.cc

Index: content/browser/web_contents/aura/overscroll_window_animation.cc
diff --git a/content/browser/web_contents/aura/overscroll_window_animation.cc b/content/browser/web_contents/aura/overscroll_window_animation.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1646a4d53bde3f694ccb5eee4d4aad13d84acc3b
--- /dev/null
+++ b/content/browser/web_contents/aura/overscroll_window_animation.cc
@@ -0,0 +1,117 @@
+// Copyright (c) 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 "content/browser/web_contents/aura/overscroll_window_animation.h"
+
+#include "ui/compositor/layer_animation_observer.h"
+#include "ui/compositor/scoped_layer_animation_settings.h"
+
+namespace content {
+
+OverscrollWindowAnimation::OverscrollWindowAnimation(
+    Delegate* delegate)
+    : delegate_(delegate),
+      direction_(NONE),
+      overscroll_cancelled_(false),
+      animation_completed_(true) {

[mfomitchev, 2015/02/19 19:04:59]

It's a bit weird initialized completed to true given that nothing completed.
Perhaps change to animation_active_ and inverse the usage?

[Nina, 2015/02/27 19:32:51]

Done.

+}
+
+OverscrollWindowAnimation::~OverscrollWindowAnimation() {
+  LOG(ERROR) << "OWA destructor";
+}
+
+void OverscrollWindowAnimation::CancelOverscroll() {
+  LOG(ERROR) << "Cancelling animation";
+  overscroll_cancelled_ = true;
+  ui::ScopedLayerAnimationSettings settings(delegate_->GetAnimator());
+  settings.SetPreemptionStrategy(
+      ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+  settings.SetTweenType(gfx::Tween::EASE_OUT);
+  settings.AddObserver(this);
+  delegate_->SetTransform(gfx::Transform());
+  direction_ = NONE;
+}
+
+void OverscrollWindowAnimation::AbortAllAnimations() {

[mfomitchev, 2015/02/19 19:04:59]

This method is called only once. Consider getting rid of it

[Nina, 2015/02/27 19:32:51]

Done.

+  delegate_->GetAnimator()->AbortAllAnimations();
+}
+
+bool OverscrollWindowAnimation::IsSlideInProgress() const {

[mfomitchev, 2015/02/19 19:04:59]

Lets call this something else. Perhaps IsAnimationInProgress?

[Nina, 2015/02/27 19:32:51]

Done.

+  return !animation_completed_;
+}
+
+void OverscrollWindowAnimation::OnImplicitAnimationsCompleted() {
+  animation_completed_ = true;
+  delegate_->OnAnimationCompleted();
+}
+
+gfx::Vector2dF OverscrollWindowAnimation::GetTranslationForOverscroll(
+    float delta_x) {
+  DCHECK(direction_ != NONE);
+  const float bounds_width = delegate_->GetContentsBounds().width();
+  if (direction_ == FORWARD)
+    return gfx::Vector2dF(std::max(-bounds_width, delta_x), 0);
+  else
+    return gfx::Vector2dF(std::min(bounds_width, delta_x), 0);
+}
+
+gfx::Rect OverscrollWindowAnimation::GetVisibleBounds() const {
+  return delegate_->GetContentsBounds();
+}
+
+bool OverscrollWindowAnimation::OnOverscrollUpdate(float delta_x,
+                                                   float delta_y) {
+  if (direction_ == NONE)
+    return false;
+  LOG(ERROR) << "OWA: OnOverscrollUpdate";
+  gfx::Vector2dF translate = GetTranslationForOverscroll(delta_x);
+  gfx::Transform transform;
+  transform.Translate(translate.x(), translate.y());
+  delegate_->SetTransform(transform);
+  return true;
+}
+
+void OverscrollWindowAnimation::OnOverscrollModeChange(
+    OverscrollMode old_mode,
+    OverscrollMode new_mode) {
+  LOG(ERROR) << "OWA: OnOverscrollModeChange";
+  AbortAllAnimations();

[mfomitchev, 2015/02/19 19:04:59]

Seems like an overkill to call this every time. We only need to call this if
there is an active animation and we are starting a new one (i.e. direction_ is
not NONE)

[Nina, 2015/02/27 19:32:51]

Done.

+  direction_ = delegate_->StartNavigation(new_mode);

[mfomitchev, 2015/02/19 19:04:59]

StartNavigation(OVERSCROLL_NONE) sounds a bit misleading..

[Nina, 2015/02/27 19:32:51]

This should no longer be the case after changing the delegate interface as we
discussed.

+
+  if (direction_ == NONE) {
+    // The user cancelled the in progress overscroll gesture.
+    // TODO(nsatragno): in this case, show a feedback animation.
+    if (IsSlideInProgress())
+      CancelOverscroll();
+    return;
+  }
+  StartAnimating();
+}
+
+void OverscrollWindowAnimation::StartAnimating() {

[mfomitchev, 2015/02/19 19:04:59]

I don't see much reason for the existence of this method..

[Nina, 2015/02/27 19:32:51]

Removed.

+  LOG(ERROR) << "OWA: StartAnimating";
+  overscroll_cancelled_ = false;
+  animation_completed_ = false;
+}
+
+void OverscrollWindowAnimation::OnOverscrollComplete(
+    OverscrollMode overscroll_mode) {
+  LOG(ERROR) << "OWA: OnOverscrollComplete";
+  delegate_->OnAnimationCompleting();
+  ui::ScopedLayerAnimationSettings settings(delegate_->GetAnimator());
+  settings.SetPreemptionStrategy(
+      ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+  settings.SetTweenType(gfx::Tween::EASE_OUT);
+  settings.AddObserver(this);
+  gfx::Transform transform;
+  int content_width = delegate_->GetContentsBounds().width();
+  float translate_x = static_cast<float>(
+      direction_ == FORWARD ? -content_width
+                            : content_width);
+  transform.Translate(translate_x, 0);
+  delegate_->SetTransform(transform);
+  direction_ = NONE;
+}
+
+}  // namespace content