Revert of Snap RWHVA and resize the legacy window on Windows whenever the ancestor window's bounds change.

content/browser/web_contents/web_contents_view_aura.cc

Index: content/browser/web_contents/web_contents_view_aura.cc
diff --git a/content/browser/web_contents/web_contents_view_aura.cc b/content/browser/web_contents/web_contents_view_aura.cc
index b387a93f24d1fd8b3fec5623e95504fb286b0283..68e28b305701b2912c29cc1f56e1018a1799c0b0 100644
--- a/content/browser/web_contents/web_contents_view_aura.cc
+++ b/content/browser/web_contents/web_contents_view_aura.cc
@@ -504,6 +504,21 @@
 #endif
   }
 
+  // Overridden from aura::WindowObserver:
+  void OnWindowHierarchyChanged(
+      const aura::WindowObserver::HierarchyChangeParams& params) override {
+    if (params.receiver != view_->window_.get() ||
+        !params.target->Contains(view_->window_.get())) {
+      return;
+    }
+
+    // Use the new parent's root window for calculating HiDPI subpixel offset.
+    RenderWidgetHostViewAura* rwhv = ToRenderWidgetHostViewAura(
+        view_->web_contents_->GetRenderWidgetHostView());
+    if (rwhv)
+      rwhv->SnapToPhysicalPixelBoundary();
+  }
+
 #if defined(OS_WIN)
   // Constrained windows are added as children of the parent's parent's view
   // which may overlap with windowed NPAPI plugins. In that case, tell the RWHV