Made Blink aware of top controls offset (Chromium-side)

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index 515d42bdbea6e2d112127ea9cb2109f515481823..dce1d42e11d071384b5f9ee1dcaaa2b82446e791 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -107,6 +107,7 @@ LayerTreeHost::LayerTreeHost(LayerTreeHostClient* client,
       settings_(settings),
       debug_state_(settings.initial_debug_state),
       top_controls_layout_height_(0.f),
+      top_controls_content_offset_(0.f),
       device_scale_factor_(1.f),
       visible_(true),
       page_scale_factor_(1.f),
@@ -347,11 +348,23 @@ void LayerTreeHost::FinishCommitOnImplThread(LayerTreeHostImpl* host_impl) {
 
   sync_tree->PassSwapPromises(&swap_promise_list_);
 
+  float top_controls_height = 0.f;
+
+  if (host_impl->top_controls_manager())
+    top_controls_height = host_impl->top_controls_manager()->controls_height();
+
+  sync_tree->set_top_controls_layout_height(top_controls_layout_height_);
+  sync_tree->set_top_controls_top_offset(top_controls_content_offset_ -
+      top_controls_height);
+  sync_tree->set_top_controls_delta(
+      sync_tree->top_controls_delta() -
+          sync_tree->sent_top_controls_delta());
+  sync_tree->set_sent_top_controls_delta(0.f);
+
   host_impl->SetUseGpuRasterization(UseGpuRasterization());
   RecordGpuRasterizationHistogram();
 
   host_impl->SetViewportSize(device_viewport_size_);
-  host_impl->SetTopControlsLayoutHeight(top_controls_layout_height_);
   host_impl->SetDeviceScaleFactor(device_scale_factor_);
   host_impl->SetDebugState(debug_state_);
   if (pending_page_scale_animation_) {
@@ -627,12 +640,19 @@ void LayerTreeHost::SetViewportSize(const gfx::Size& device_viewport_size) {
   SetNeedsCommit();
 }
 
-void LayerTreeHost::SetTopControlsLayoutHeight(
-    float top_controls_layout_height) {
-  if (top_controls_layout_height_ == top_controls_layout_height)
+void LayerTreeHost::SetTopControlsLayoutHeight(float height) {
+  if (top_controls_layout_height_ == height)
+    return;
+
+  top_controls_layout_height_ = height;
+  SetNeedsCommit();
+}
+
+void LayerTreeHost::SetTopControlsContentOffset(float offset) {
+  if (top_controls_content_offset_ == offset)
     return;
 
-  top_controls_layout_height_ = top_controls_layout_height;
+  top_controls_content_offset_ = offset;
   SetNeedsCommit();
 }
 
@@ -1072,7 +1092,9 @@ void LayerTreeHost::ApplyScrollAndScale(ScrollAndScaleSet* info) {
   }
 
   if (!inner_viewport_scroll_delta.IsZero() ||
-      !outer_viewport_scroll_delta.IsZero() || info->page_scale_delta != 1.f) {
+      !outer_viewport_scroll_delta.IsZero() ||
+      info->page_scale_delta != 1.f ||
+      info->top_controls_delta) {
     // SetScrollOffsetFromImplSide above could have destroyed the tree,
     // so re-get this layer before doing anything to it.
 
@@ -1091,9 +1113,10 @@ void LayerTreeHost::ApplyScrollAndScale(ScrollAndScaleSet* info) {
     }
     ApplyPageScaleDeltaFromImplSide(info->page_scale_delta);
 
-    client_->ApplyScrollAndScale(
+    client_->ApplyViewportDeltas(
         inner_viewport_scroll_delta + outer_viewport_scroll_delta,
-        info->page_scale_delta);
+        info->page_scale_delta,
+        info->top_controls_delta);
   }
 }