wm: Fix regression with dragging windows with transforms.

In crrev.com/c/2238652, we modified the drag window copy to share codes
with WindowMirrorView. For this case, we skipped setting a transform in
Layout but we actually need to set it to identity since mirroring
layers will copy transforms (case for dragging overview windows). Copies
some more layer properties that may be on the original window.

Test: added test, manual
Bug: 1113429
Change-Id: I7874d733be5026c0785c32cc5ceafb529653b4cd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2340791
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796139}

ash/wm/drag_window_controller.cc

@@ -96,6 +96,10 @@ class DragWindowController::DragWindowDetails {
                                       window->parent(), &bounds);
     window->SetBounds(bounds);
     window->SetTransform(original_window->transform());
+    window->layer()->SetClipRect(original_window->layer()->clip_rect());
+    window->layer()->SetRoundedCornerRadius(
+        original_window->layer()->rounded_corner_radii());
+    window->layer()->SetIsFastRoundedCorner(true);
     widget_->SetOpacity(opacity);
   }
 

ash/wm/window_mirror_view.cc

@@ -15,6 +15,7 @@
 #include "ui/aura/window_occlusion_tracker.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_tree_owner.h"
+#include "ui/gfx/transform.h"
 #include "ui/views/widget/widget.h"
 #include "ui/wm/core/window_util.h"
 
@@ -77,8 +78,10 @@ void WindowMirrorView::Layout() {
   // Position at 0, 0.
   GetMirrorLayer()->SetBounds(gfx::Rect(GetMirrorLayer()->bounds().size()));
 
-  if (show_non_client_view_)
+  if (show_non_client_view_) {
+    GetMirrorLayer()->SetTransform(gfx::Transform());
     return;
+  }
 
   gfx::Transform transform;
   gfx::Rect client_area_bounds = GetClientAreaBounds();
@@ -123,6 +126,10 @@ void WindowMirrorView::RemovedFromWidget() {
   target_ = nullptr;
 }
 
+ui::Layer* WindowMirrorView::GetMirrorLayerForTesting() {
+  return GetMirrorLayer();
+}
+
 void WindowMirrorView::InitLayerOwner() {
   layer_owner_ = ::wm::MirrorLayers(source_, false /* sync_bounds */);
 

ash/wm/window_mirror_view.h

@@ -49,6 +49,8 @@ class ASH_EXPORT WindowMirrorView : public views::View,
   void AddedToWidget() override;
   void RemovedFromWidget() override;
 
+  ui::Layer* GetMirrorLayerForTesting();
+
  protected:
   virtual void InitLayerOwner();
 

ash/wm/window_mirror_view_unittest.cc

@@ -8,6 +8,7 @@
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/window_occlusion_tracker.h"
 #include "ui/gfx/geometry/size.h"
+#include "ui/gfx/transform.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_delegate.h"
 
@@ -36,5 +37,26 @@ TEST_F(WindowMirrorViewTest, LocalWindowOcclusionMadeVisible) {
             widget_window->occlusion_state());
 }
 
+// Tests that a mirror view that mirrors a window with an existing transform
+// does not copy that transform onto its mirror layer (and then putting the
+// mirror layer offscreen). Regression test for https://crbug.com/1113429.
+TEST_F(WindowMirrorViewTest, MirrorLayerHasNoTransformWhenNonClientViewShown) {
+  // Create a window that has a transform already. When the layer is mirrored,
+  // the transform will be copied with it.
+  auto widget = CreateTestWidget();
+  aura::Window* widget_window = widget->GetNativeWindow();
+  const gfx::Transform transform(1.f, 0.f, 0.f, 1.f, 100.f, 100.f);
+  widget_window->SetTransform(transform);
+
+  auto mirror_widget = CreateTestWidget();
+  auto mirror_view = std::make_unique<WindowMirrorView>(
+      widget_window, /*trilinear_filtering_on_init=*/false,
+      /*show_non_client_view=*/true);
+  mirror_view->RecreateMirrorLayers();
+
+  EXPECT_TRUE(
+      mirror_view->GetMirrorLayerForTesting()->transform().IsIdentity());
+}
+
 }  // namespace
 }  // namespace ash