Revert "Reland "[UI] Disable bubble shadows and rounded corners without compositing""

This reverts commit b364074b0dd9fac88f747f1eea7571c8d1dafc6e.

Reason for revert: same issue: https://g-issues.chromium.org/issues/354237196

Original change's description:
> Reland "[UI] Disable bubble shadows and rounded corners without compositing"
>
> This is a reland of commit 7e6de0490e9fa5f3595eb9fb420241bf5bad0c50
>
> Original change's description:
> > [UI] Disable bubble shadows and rounded corners without compositing
> >
> > R=sky
> >
> > Change-Id: I1d6e29863ee5480faef7d87b3095efe0df2510a6
> > Bug: None
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5719018
> > Auto-Submit: Thomas Anderson <thomasanderson@chromium.org>
> > Reviewed-by: Scott Violet <sky@chromium.org>
> > Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
> > Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
> > Cr-Commit-Position: refs/heads/main@{#1330300}
>
> Bug: None
> Change-Id: Ief050bcd469c6de19256adeaa03e2360acaa1fdb
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5727138
> Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
> Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
> Reviewed-by: Scott Violet <sky@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1330568}

Bug: None
Change-Id: I93d0e8ff3de486740c7604a2b4f99fb5769e8d47
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5727255
Reviewed-by: Łukasz Anforowicz <lukasza@chromium.org>
Owners-Override: Łukasz Anforowicz <lukasza@chromium.org>
Commit-Queue: Łukasz Anforowicz <lukasza@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1330710}
diff --git a/ui/views/bubble/bubble_dialog_delegate_view.cc b/ui/views/bubble/bubble_dialog_delegate_view.cc
index 6e11e5b..11b7501 100644
--- a/ui/views/bubble/bubble_dialog_delegate_view.cc
+++ b/ui/views/bubble/bubble_dialog_delegate_view.cc
@@ -668,9 +668,6 @@
 
 
 BubbleBorder::Shadow BubbleDialogDelegate::GetShadow() const {
-  if (!Widget::IsWindowCompositingSupported()) {
-    return BubbleBorder::Shadow::NO_SHADOW;
-  }
   return shadow_;
 }
 
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index 6173b08..4ac14816 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -377,10 +377,12 @@
 
 // static
 bool Widget::IsWindowCompositingSupported() {
-#if BUILDFLAG(IS_OZONE)
+#if BUILDFLAG(IS_WIN)
+  return true;
+#elif BUILDFLAG(IS_OZONE)
   return ui::OzonePlatform::GetInstance()->IsWindowCompositingSupported();
 #else
-  return true;
+  return false;
 #endif
 }
 
diff --git a/ui/views/window/dialog_delegate.cc b/ui/views/window/dialog_delegate.cc
index e015de5..e1ac8ad 100644
--- a/ui/views/window/dialog_delegate.cc
+++ b/ui/views/window/dialog_delegate.cc
@@ -524,9 +524,6 @@
 }
 
 int DialogDelegate::GetCornerRadius() const {
-  if (!Widget::IsWindowCompositingSupported()) {
-    return 0;
-  }
 #if BUILDFLAG(IS_MAC)
   // TODO(crbug.com/40144839): On Mac MODAL_TYPE_WINDOW is implemented using
   // sheets which causes visual artifacts when corner radius is increased for