Introduce bottom controls to CC and let it respond to scrolling

cc/trees/layer_tree.cc

 // Copyright 2016 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/trees/layer_tree.h"
 
 #include "base/auto_reset.h"
 #include "base/time/time.h"
 #include "cc/animation/animation_host.h"
 #include "cc/input/page_scale_animation.h"
@@ skipping 27 matching lines @@
 
   return layer;
 }
 
 }  // namespace
 
 LayerTree::Inputs::Inputs()
     : top_controls_height(0.f),
       top_controls_shown_ratio(0.f),
       top_controls_shrink_blink_size(false),
+      bottom_controls_height(0.f),
       device_scale_factor(1.f),
       painted_device_scale_factor(1.f),
       page_scale_factor(1.f),
       min_page_scale_factor(1.f),
       max_page_scale_factor(1.f),
       background_color(SK_ColorWHITE),
       has_transparent_background(false),
       have_scroll_event_handlers(false),
       event_listener_properties() {}
 
@@ skipping 108 matching lines @@
 }
 
 void LayerTree::SetTopControlsShownRatio(float ratio) {
   if (inputs_.top_controls_shown_ratio == ratio)
     return;
 
   inputs_.top_controls_shown_ratio = ratio;
   SetNeedsCommit();
 }
 
+void LayerTree::SetBottomControlsHeight(float height) {
+  if (inputs_.bottom_controls_height == height)
+    return;
+
+  inputs_.bottom_controls_height = height;
+  SetNeedsCommit();
+}
+
 void LayerTree::SetPageScaleFactorAndLimits(float page_scale_factor,
                                             float min_page_scale_factor,
                                             float max_page_scale_factor) {
   if (inputs_.page_scale_factor == page_scale_factor &&
       inputs_.min_page_scale_factor == min_page_scale_factor &&
       inputs_.max_page_scale_factor == max_page_scale_factor)
     return;
 
   inputs_.page_scale_factor = page_scale_factor;
   inputs_.min_page_scale_factor = min_page_scale_factor;
@@ skipping 191 matching lines @@
   // Setting property trees must happen before pushing the page scale.
   tree_impl->SetPropertyTrees(&property_trees_);
 
   tree_impl->PushPageScaleFromMainThread(inputs_.page_scale_factor,
                                          inputs_.min_page_scale_factor,
                                          inputs_.max_page_scale_factor);
 
   tree_impl->set_top_controls_shrink_blink_size(
       inputs_.top_controls_shrink_blink_size);
   tree_impl->set_top_controls_height(inputs_.top_controls_height);
+  tree_impl->set_bottom_controls_height(inputs_.bottom_controls_height);
   tree_impl->PushTopControlsFromMainThread(inputs_.top_controls_shown_ratio);
   tree_impl->elastic_overscroll()->PushFromMainThread(elastic_overscroll_);
   if (tree_impl->IsActiveTree())
     tree_impl->elastic_overscroll()->PushPendingToActive();
 
   tree_impl->set_painted_device_scale_factor(
       inputs_.painted_device_scale_factor);
 
   if (inputs_.pending_page_scale_animation) {
     tree_impl->SetPendingPageScaleAnimation(
@@ skipping 133 matching lines @@
   // updated for other reasons. All layers that at this point are part of the
   // layer tree are valid, so it is OK that they have a valid sequence number.
   int seq_num = property_trees_.sequence_number;
   LayerTreeHostCommon::CallFunctionForEveryLayer(
       layer_tree_host_, [seq_num](Layer* layer) {
         layer->set_property_tree_sequence_number(seq_num);
       });
 }
 
 }  // namespace cc