Allow changing top controls height

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index bb1be9856d093663f5533a2c4a6cff40c0a50cfd..53085fcbd7ad21e7245d954f69c562b5f4583f98 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -259,15 +259,8 @@ LayerTreeHostImpl::LayerTreeHostImpl(
   if (settings.calculate_top_controls_position) {
     top_controls_manager_ =
         TopControlsManager::Create(this,
-                                   settings.top_controls_height,
                                    settings.top_controls_show_threshold,
                                    settings.top_controls_hide_threshold);
-
-    // TODO(bokan): This is a quick fix. The browser should lock the top
-    // controls to shown on creation but this appears not to work. Tracked
-    // in crbug.com/417680.
-    // Initialize with top controls showing.
-    SetControlsTopOffset(0.f);
   }
 }
 
@@ -1633,9 +1626,13 @@ void LayerTreeHostImpl::UpdateViewportContainerSizes() {
 
   // Adjust the inner viewport by shrinking/expanding the container to account
   // for the change in top controls height since the last Resize from Blink.
+  float top_controls_layout_height =
+      active_tree_->top_controls_shrink_blink_size()
+          ? active_tree_->top_controls_height()
+          : 0.f;
   inner_container->SetBoundsDelta(
-      gfx::Vector2dF(0, active_tree_->top_controls_layout_height() -
-          active_tree_->total_top_controls_content_offset()));
+      gfx::Vector2dF(0, top_controls_layout_height -
+                            active_tree_->total_top_controls_content_offset()));
 
   if (!outer_container || outer_container->BoundsForScrolling().IsEmpty())
     return;
@@ -1658,11 +1655,26 @@ void LayerTreeHostImpl::UpdateViewportContainerSizes() {
   anchor.ResetViewportToAnchoredPosition();
 }
 
-void LayerTreeHostImpl::SetTopControlsLayoutHeight(float height) {
-  if (active_tree_->top_controls_layout_height() == height)
+void LayerTreeHostImpl::SetTopControlsHeight(float height) {
+  if (active_tree_->top_controls_height() == height)
+    return;
+
+  // Adjust the delta to maintain the current top controls offset.
+  active_tree_->set_top_controls_delta(active_tree_->top_controls_delta() -
+                                       active_tree_->top_controls_height() +
+                                       height);
+  active_tree_->set_top_controls_height(height);
+  UpdateViewportContainerSizes();
+  SetNeedsRedraw();
+  active_tree_->set_needs_update_draw_properties();
+  SetFullRootLayerDamage();
+}
+
+void LayerTreeHostImpl::SetTopControlsShrinkBlinkSize(bool shrink) {

[aelias_OOO_until_Jul13, 2014/11/21 04:19:21]

I don't see any calls to this method in this patch.  You want to call it during
activation like the other method.  I expect this will cause bottom fixed-pos
elements to behave incorrectly, try for example mobile http://forbes.com/.

[aelias_OOO_until_Jul13, 2014/11/21 04:19:21]

I don't see any calls to this method in this patch.  You want to call it during
activation like the other method.  I expect this will cause bottom fixed-pos
elements to behave incorrectly, try for example mobile http://forbes.com/.

[David Trainor- moved to gerrit, 2014/11/22 00:35:30]

Good call.  Removed.

+  if (active_tree_->top_controls_shrink_blink_size() == shrink)
     return;
 
-  active_tree_->set_top_controls_layout_height(height);
+  active_tree_->set_top_controls_shrink_blink_size(shrink);
   UpdateViewportContainerSizes();
   SetFullRootLayerDamage();
 }
@@ -1741,6 +1753,7 @@ void LayerTreeHostImpl::CreatePendingTree() {
   pending_tree_->set_top_controls_delta(
       active_tree_->top_controls_delta() -
       active_tree_->sent_top_controls_delta());
+  pending_tree_->set_top_controls_height(active_tree_->top_controls_height());
 
   client_->OnCanDrawStateChanged(CanDraw());
   TRACE_EVENT_ASYNC_BEGIN0("cc", "PendingTree:waiting", pending_tree_.get());
@@ -1777,6 +1790,8 @@ void LayerTreeHostImpl::ActivateSyncTree() {
         root_layer_scroll_offset_delegate_);
 
     if (top_controls_manager_) {
+      top_controls_manager_->SetTopControlsHeight(
+          active_tree_->top_controls_height());
       top_controls_manager_->SetControlsTopOffset(
           active_tree_->total_top_controls_content_offset() -
           top_controls_manager_->top_controls_height());
@@ -2242,13 +2257,13 @@ void LayerTreeHostImpl::DidChangeTopControlsPosition() {
 
 void LayerTreeHostImpl::SetControlsTopOffset(float offset) {
   float current_top_offset = active_tree_->top_controls_content_offset() -
-      top_controls_manager_->top_controls_height();
+                             active_tree_->top_controls_height();
   active_tree_->set_top_controls_delta(offset - current_top_offset);
 }
 
 float LayerTreeHostImpl::ControlsTopOffset() const {
   return active_tree_->total_top_controls_content_offset() -
-      top_controls_manager_->top_controls_height();
+         active_tree_->top_controls_height();
 }
 
 void LayerTreeHostImpl::BindToClient(InputHandlerClient* client) {