app_list: Fix shadow bleeds over launcher button and steals mouse events

ui/aura/test/test_window_delegate.cc

Index: ui/aura/test/test_window_delegate.cc
diff --git a/ui/aura/test/test_window_delegate.cc b/ui/aura/test/test_window_delegate.cc
index 52b50d7788f12a8bd4f2befa6b6d4d66ed2c67b7..54a342e7fef15c955568e1b0fe788bfe918c3342 100644
--- a/ui/aura/test/test_window_delegate.cc
+++ b/ui/aura/test/test_window_delegate.cc
@@ -8,6 +8,8 @@
 #include "ui/aura/window.h"
 #include "ui/base/hit_test.h"
 #include "ui/gfx/canvas.h"
+#include "ui/gfx/path.h"
+#include "ui/gfx/skia_util.h"
 
 namespace aura {
 namespace test {
@@ -82,6 +84,12 @@ void TestWindowDelegate::OnWindowDestroyed() {
 void TestWindowDelegate::OnWindowVisibilityChanged(bool visible) {
 }
 
+bool TestWindowDelegate::HasHitTestMask() const {
+  return false;
+}
+
+void TestWindowDelegate::GetHitTestMask(gfx::Path* mask) const {
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 // ColorTestWindowDelegate
@@ -104,5 +112,20 @@ void ColorTestWindowDelegate::OnPaint(gfx::Canvas* canvas) {
   canvas->DrawColor(color_, SkXfermode::kSrc_Mode);
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// MaskedWindowDelegate
+
+MaskedWindowDelegate::MaskedWindowDelegate(const gfx::Rect mask_rect)
+    : mask_rect_(mask_rect) {
+}
+
+bool MaskedWindowDelegate::HasHitTestMask() const {
+  return true;
+}
+
+void MaskedWindowDelegate::GetHitTestMask(gfx::Path* mask) const {
+  mask->addRect(RectToSkRect(mask_rect_));
+}
+
 }  // namespace test
 }  // namespace aura