Introduce bottom controls to CC and let it respond to scrolling

content/renderer/render_widget.cc

 // Copyright (c) 2012 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/renderer/render_widget.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 1003 matching lines @@
   if (resizing_mode_selector_->NeverUsesSynchronousResize()) {
     // A resize ack shouldn't be requested if we have not ACK'd the previous
     // one.
     DCHECK(!params.needs_resize_ack || !next_paint_is_resize_ack());
   }
 
   // Ignore this during shutdown.
   if (!webwidget_)
     return;
 
-  if (compositor_)
+  if (compositor_) {
     compositor_->setViewportSize(params.physical_backing_size);
+    compositor_->setBottomControlHeight(params.bottom_controls_height);
+  }
 
   visible_viewport_size_ = params.visible_viewport_size;
   resizer_rect_ = params.resizer_rect;
 
   // NOTE: We may have entered fullscreen mode without changing our size.
   bool fullscreen_change =
       is_fullscreen_granted_ != params.is_fullscreen_granted;
   is_fullscreen_granted_ = params.is_fullscreen_granted;
   display_mode_ = params.display_mode;
 
@@ skipping 1029 matching lines @@
 void RenderWidget::requestPointerUnlock() {
   mouse_lock_dispatcher_->UnlockMouse(webwidget_mouse_lock_target_.get());
 }
 
 bool RenderWidget::isPointerLocked() {
   return mouse_lock_dispatcher_->IsMouseLockedTo(
       webwidget_mouse_lock_target_.get());
 }
 
 }  // namespace content