Add unittests to check that null/empty window shapes work.

Followup to https://codereview.chromium.org/602013002/, which fixes a bug with empty window shapes not being handled properly on CrOS.

BUG=417014

Review URL: https://codereview.chromium.org/607623002

Cr-Commit-Position: refs/heads/master@{#297337}

chrome/browser/ui/views/apps/shaped_app_window_targeter_unittest.cc

@@ -72,6 +72,30 @@ TEST_F(ShapedAppWindowTargeterTest, HitTestBasic) {
   }
 
   scoped_ptr<SkRegion> region(new SkRegion);
+  region->op(SkIRect::MakeXYWH(0, 0, 0, 0), SkRegion::kUnion_Op);
+  app_window()->UpdateShape(region.Pass());
+  {
+    // With an empty custom shape, all events within the window should fall
+    // through to the root window.
+    ui::MouseEvent move(ui::ET_MOUSE_MOVED,
+                        gfx::Point(40, 40), gfx::Point(40, 40),
+                        ui::EF_NONE, ui::EF_NONE);
+    ui::EventDispatchDetails details =
+        event_processor()->OnEventFromSource(&move);
+    ASSERT_FALSE(details.dispatcher_destroyed);
+    EXPECT_EQ(root_window(), move.target());
+  }
+
+  // Window shape (global coordinates)
+  //    30       70    90        130
+  //  30 +        +-----+
+  //       .      |     |             <- mouse move (40,40)
+  //  70 +--------+     +---------+
+  //     |           .            |   <- mouse move (80,80)
+  //  90 +--------+     +---------+
+  //              |     |
+  // 130          +-----+
+  region.reset(new SkRegion);
   region->op(SkIRect::MakeXYWH(40, 0, 20, 100), SkRegion::kUnion_Op);
   region->op(SkIRect::MakeXYWH(0, 40, 100, 20), SkRegion::kUnion_Op);
   app_window()->UpdateShape(region.Pass());

ui/views/widget/desktop_aura/x11_topmost_window_finder_interactive_uitest.cc

@@ -356,6 +356,51 @@ TEST_F(X11TopmostWindowFinderTest, NonRectangular) {
   XDestroyWindow(xdisplay(), xid2);
 }
 
+// Test that a window with an empty shape are properly handled.
+TEST_F(X11TopmostWindowFinderTest, NonRectangularEmptyShape) {
+  if (!ui::IsShapeExtensionAvailable())
+    return;
+
+  scoped_ptr<Widget> widget1(
+      CreateAndShowWidget(gfx::Rect(100, 100, 100, 100)));
+  XID xid1 = widget1->GetNativeWindow()->GetHost()->GetAcceleratedWidget();
+  SkRegion* skregion1 = new SkRegion;
+  skregion1->op(SkIRect::MakeXYWH(0, 0, 0, 0), SkRegion::kUnion_Op);
+  // Widget takes ownership of |skregion1|.
+  widget1->SetShape(skregion1);
+
+  XID xids[] = { xid1 };
+  StackingClientListWaiter stack_waiter(xids, arraysize(xids));
+  stack_waiter.Wait();
+  ui::X11EventSource::GetInstance()->DispatchXEvents();
+
+  EXPECT_NE(xid1, FindTopmostXWindowAt(105, 105));
+}
+
+// Test that setting a Null shape removes the shape.
+TEST_F(X11TopmostWindowFinderTest, NonRectangularNullShape) {
+  if (!ui::IsShapeExtensionAvailable())
+    return;
+
+  scoped_ptr<Widget> widget1(
+      CreateAndShowWidget(gfx::Rect(100, 100, 100, 100)));
+  XID xid1 = widget1->GetNativeWindow()->GetHost()->GetAcceleratedWidget();
+  SkRegion* skregion1 = new SkRegion;
+  skregion1->op(SkIRect::MakeXYWH(0, 0, 0, 0), SkRegion::kUnion_Op);
+  // Widget takes ownership of |skregion1|.
+  widget1->SetShape(skregion1);
+
+  // Remove the shape - this is now just a normal window.
+  widget1->SetShape(NULL);
+
+  XID xids[] = { xid1 };
+  StackingClientListWaiter stack_waiter(xids, arraysize(xids));
+  stack_waiter.Wait();
+  ui::X11EventSource::GetInstance()->DispatchXEvents();
+
+  EXPECT_EQ(xid1, FindTopmostXWindowAt(105, 105));
+}
+
 // Test that the TopmostWindowFinder finds windows which belong to menus
 // (which may or may not belong to Chrome).
 TEST_F(X11TopmostWindowFinderTest, Menu) {