(Reland) Always create top controls manager

cc/input/top_controls_manager.cc

 // Copyright 2013 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 "cc/input/top_controls_manager.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "cc/animation/keyframed_animation_curve.h"
@@ skipping 83 matching lines @@
 }
 
 void TopControlsManager::ScrollBegin() {
   DCHECK(!pinch_gesture_active_);
   ResetAnimations();
   ResetBaseline();
 }
 
 gfx::Vector2dF TopControlsManager::ScrollBy(
     const gfx::Vector2dF& pending_delta) {
+  if (!TopControlsHeight())
+    return pending_delta;
+
   if (pinch_gesture_active_)
     return pending_delta;
 
   if (!TopControlsHeight())
     return pending_delta;
 
   if (permitted_state_ == SHOWN && pending_delta.y() > 0)
     return pending_delta;
   else if (permitted_state_ == HIDDEN && pending_delta.y() < 0)
     return pending_delta;
@@ skipping 62 matching lines @@
 }
 
 void TopControlsManager::SetupAnimation(AnimationDirection direction) {
   DCHECK_NE(NO_ANIMATION, direction);
   DCHECK_IMPLIES(direction == HIDING_CONTROLS, TopControlsShownRatio() > 0.f);
   DCHECK_IMPLIES(direction == SHOWING_CONTROLS, TopControlsShownRatio() < 1.f);
 
   if (top_controls_animation_ && animation_direction_ == direction)
     return;
 
+  if (!TopControlsHeight()) {
+    client_->SetCurrentTopControlsShownRatio(
+        direction == HIDING_CONTROLS ? 0.f : 1.f);
+    return;
+  }
+
   top_controls_animation_ = KeyframedFloatAnimationCurve::Create();
   base::TimeDelta start_time = gfx::FrameTime::Now() - base::TimeTicks();
   top_controls_animation_->AddKeyframe(
       FloatKeyframe::Create(start_time, TopControlsShownRatio(), nullptr));
   float max_ending_ratio = (direction == SHOWING_CONTROLS ? 1 : -1);
   top_controls_animation_->AddKeyframe(FloatKeyframe::Create(
       start_time + base::TimeDelta::FromMilliseconds(kShowHideMaxDurationMs),
       TopControlsShownRatio() + max_ending_ratio,
       EaseTimingFunction::Create()));
   animation_direction_ = direction;
@@ skipping 32 matching lines @@
   }
   return false;
 }
 
 void TopControlsManager::ResetBaseline() {
   accumulated_scroll_delta_ = 0.f;
   baseline_content_offset_ = ContentTopOffset();
 }
 
 }  // namespace cc