Reland "Add drop shadow support for popups on Windows."

This is a reland of f8ead841

The build break for win-jumbo-rel is fixed in patch 2.

Original change's description:
> Add drop shadow support for popups on Windows.
>
> This CL adds drop shadow support for popups on Windows when
> the FormControlsRefresh feature is enabled.
>
> In order to add the drop shadow, the Window used for popups (TYPE_MENU)
> is decorated with the WS_THICKFRAME style. Since WS_THICKFRAME also
> provides a frame, the remove_standard_frame flag is set as we are interested
> in keeping just the drop shadow.
>
> Since drop shadow is not supported on Windows versions without DWM composition,
> then the drop shadow is replaced by a thin-line border by using the
> WS_BORDER style.
>
> Bug: 1000898
> Change-Id: I04588d8d1703cb98f4b7a239f9cf46d742324a1c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1786247
> Reviewed-by: Scott Violet <sky@chromium.org>
> Reviewed-by: Mason Freed <masonfreed@chromium.org>
> Commit-Queue: Ionel Popescu <iopopesc@microsoft.com>
> Cr-Commit-Position: refs/heads/master@{#695655}

Bug: 1000898, 1008725
Change-Id: I9393f9cb8d2e998d4f5e66d2e77290238bbda16d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1829877Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Mason Freed <masonfreed@chromium.org>
Commit-Queue: Ionel Popescu <iopopesc@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#700889}

ui/views/widget/desktop_aura/desktop_native_widget_aura.cc

@@ -26,6 +26,7 @@
 #include "ui/base/class_property.h"
 #include "ui/base/hit_test.h"
 #include "ui/base/ime/input_method.h"
+#include "ui/base/ui_base_features.h"
 #include "ui/compositor/layer.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/geometry/point_conversions.h"
@@ -99,6 +100,13 @@ class DesktopNativeWidgetTopLevelHandler : public aura::WindowObserver {
     init_params.type = full_screen ? Widget::InitParams::TYPE_WINDOW
                                    : is_menu ? Widget::InitParams::TYPE_MENU
                                              : Widget::InitParams::TYPE_POPUP;
+#if defined(OS_WIN)
+    // For menus, on Windows versions that support drop shadow remove
+    // the standard frame in order to keep just the shadow.
+    if (::features::IsFormControlsRefreshEnabled() &&
+        init_params.type == Widget::InitParams::TYPE_MENU)
+      init_params.remove_standard_frame = true;
+#endif
     init_params.bounds = bounds;
     init_params.ownership = Widget::InitParams::NATIVE_WIDGET_OWNS_WIDGET;
     init_params.layer_type = ui::LAYER_NOT_DRAWN;

ui/views/widget/widget_hwnd_utils.cc

@@ -9,6 +9,7 @@
 #include "base/command_line.h"
 #include "build/build_config.h"
 #include "ui/base/l10n/l10n_util_win.h"
+#include "ui/base/ui_base_features.h"
 #include "ui/base/ui_base_switches.h"
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/views/win/hwnd_message_handler.h"
@@ -108,6 +109,15 @@ void CalculateWindowStylesFromInitParams(
       break;
     case Widget::InitParams::TYPE_MENU:
       *style |= WS_POPUP;
+      if (::features::IsFormControlsRefreshEnabled() &&
+          params.remove_standard_frame) {
+        // If the platform doesn't support drop shadow, decorate the Window
+        // with just a border.
+        if (ui::win::IsAeroGlassEnabled())
+          *style |= WS_THICKFRAME;
+        else
+          *style |= WS_BORDER;
+      }
       break;
     case Widget::InitParams::TYPE_TOOLTIP:
       *style |= WS_POPUP;