Adds functionality to anchor widgets to the top-of-window views in immersive mode

chrome/browser/ui/views/frame/top_container_view.cc

Index: chrome/browser/ui/views/frame/top_container_view.cc
diff --git a/chrome/browser/ui/views/frame/top_container_view.cc b/chrome/browser/ui/views/frame/top_container_view.cc
index 8e4e6a3eb184da672d5fb96a8330cc09c2b5a295..d9768545fa2a16e414509574d472ca70250e50bd 100644
--- a/chrome/browser/ui/views/frame/top_container_view.cc
+++ b/chrome/browser/ui/views/frame/top_container_view.cc
@@ -15,6 +15,24 @@ TopContainerView::TopContainerView(BrowserView* browser_view)
 TopContainerView::~TopContainerView() {
 }
 
+gfx::Rect TopContainerView::GetTargetBoundsInScreen() const {
+  if (!parent())
+    return bounds();
+
+  // Compute transform relative to parent.
+  gfx::Transform transform;
+  if (layer())
+    transform = layer()->GetTargetTransform();
+  gfx::Transform translation;
+  translation.Translate(static_cast<float>(GetMirroredX()),
+                        static_cast<float>(y()));
+  transform.ConcatTransform(translation);
+
+  gfx::Point origin(parent()->GetBoundsInScreen().origin());
+  transform.TransformPoint(origin);
+  return gfx::Rect(origin, size());
+}
+
 gfx::Size TopContainerView::GetPreferredSize() {
   // The view wants to be as wide as its parent and tall enough to fully show
   // its last child view.
@@ -27,6 +45,13 @@ std::string TopContainerView::GetClassName() const {
   return "TopContainerView";
 }
 
+void TopContainerView::OnBoundsChanged(const gfx::Rect& previous_bounds) {
+  ImmersiveModeController* immersive_controller =
+      browser_view_->immersive_mode_controller();
+  if (immersive_controller->IsEnabled())
+    immersive_controller->OnTopContainerBoundsChanged();
+}
+
 void TopContainerView::PaintChildren(gfx::Canvas* canvas) {
   if (browser_view_->immersive_mode_controller()->IsRevealed()) {
     // Top-views depend on parts of the frame (themes, window buttons) being