ws: Fix WindowTargeter touch event location check

Use event.location() + ScreenPosition client in FindTargetInRootWindow:
 - location() is in |root_window| coordinates for the ws and clients
 - root_location() is *not* in |root_window| coordinates for clients:
   - |root_window| is the client-root (the top-level client app window)
   - root_location() is Ash's display-root coords (full display bounds)

Add a WindowTreeTest for event locations and root locations.
Add a WindowTargeterTest for FindTargetInRootWindow and regressions.

Bug: 873763, 793916
Test: KSV (Ctrl-Alt-/), Arc, Mash, 2nd display, etc. touch input works.
Change-Id: I7ae541203181f9fc5c65449a10ca927f90d29d96
Reviewed-on: https://chromium-review.googlesource.com/1176462
Commit-Queue: Michael Wasserman <msw@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583488}

services/ui/ws2/window_tree_unittest.cc

@@ -353,6 +353,45 @@ TEST(WindowTreeTest, WindowToWindowData) {
           data->properties[ui::mojom::WindowManager::kAlwaysOnTop_Property]));
 }
 
+TEST(WindowTreeTest, EventLocation) {
+  WindowServiceTestSetup setup;
+  TestWindowTreeClient* window_tree_client = setup.window_tree_client();
+  aura::Window* top_level =
+      setup.window_tree_test_helper()->NewTopLevelWindow();
+  ASSERT_TRUE(top_level);
+
+  top_level->Show();
+  top_level->SetBounds(gfx::Rect(10, 20, 100, 100));
+
+  // Add a child Window that covers the bottom half of the top-level window.
+  aura::Window* window = setup.window_tree_test_helper()->NewWindow();
+  ASSERT_TRUE(window);
+  window->Show();
+  window->SetBounds(gfx::Rect(0, 50, 100, 50));
+  top_level->AddChild(window);
+
+  test::EventGenerator event_generator(setup.root());
+  event_generator.MoveMouseTo(33, 44);
+  ASSERT_EQ(1u, window_tree_client->input_events().size());
+  TestWindowTreeClient::InputEvent event1 = window_tree_client->PopInputEvent();
+  ASSERT_TRUE(event1.event->IsLocatedEvent());
+  ui::LocatedEvent* located_event1 = event1.event->AsLocatedEvent();
+  // The location is in the top-level's (client-root) coordinate system.
+  EXPECT_EQ(gfx::Point(23, 24), located_event1->location());
+  // The root location is in the display's (display-root) coordinate system.
+  EXPECT_EQ(gfx::Point(33, 44), located_event1->root_location());
+
+  event_generator.MoveMouseTo(55, 66);
+  ASSERT_EQ(1u, window_tree_client->input_events().size());
+  TestWindowTreeClient::InputEvent event2 = window_tree_client->PopInputEvent();
+  ASSERT_TRUE(event2.event->IsLocatedEvent());
+  ui::LocatedEvent* located_event2 = event2.event->AsLocatedEvent();
+  // The location is in the top-level's (client-root) coordinate system.
+  EXPECT_EQ(gfx::Point(45, 46), located_event2->location());
+  // The root location is in the display's (display-root) coordinate system.
+  EXPECT_EQ(gfx::Point(55, 66), located_event2->root_location());
+}
+
 TEST(WindowTreeTest, MovePressDragRelease) {
   WindowServiceTestSetup setup;
   TestWindowTreeClient* window_tree_client = setup.window_tree_client();

ui/aura/window_targeter.cc

@@ -127,7 +127,11 @@ Window* WindowTargeter::FindTargetInRootWindow(Window* root_window,
     // This is used for bezel gesture events (eg. swiping in from screen edge).
     display::Display display =
         display::Screen::GetScreen()->GetDisplayNearestWindow(root_window);
-    gfx::Point screen_location = event.root_location();
+    // event.location() is in |root_window|'s coordinate system at this point.
+    // Using event.root_location() breaks calculations in mus clients, because
+    // event.root_location() is in the display-root's coordinate system, but
+    // |root_window| is actually the top-level window of the mus client.
+    gfx::Point screen_location = event.location();
     if (client::GetScreenPositionClient(root_window)) {
       client::GetScreenPositionClient(root_window)
           ->ConvertPointToScreen(root_window, &screen_location);

ui/aura/window_targeter_unittest.cc

@@ -11,6 +11,8 @@
 #include "ui/aura/test/aura_test_base.h"
 #include "ui/aura/test/test_window_delegate.h"
 #include "ui/aura/window.h"
+#include "ui/display/display.h"
+#include "ui/display/screen.h"
 #include "ui/events/event_utils.h"
 #include "ui/events/test/test_event_handler.h"
 
@@ -56,12 +58,10 @@ TEST_P(WindowTargeterTest, Basic) {
   Window* one = CreateNormalWindow(2, window.get(), &delegate);
   Window* two = CreateNormalWindow(3, window.get(), &delegate);
 
-  window->SetBounds(gfx::Rect(0, 0, 100, 100));
+  window->SetBounds(gfx::Rect(0, 0, 1000, 1000));
   one->SetBounds(gfx::Rect(0, 0, 500, 100));
   two->SetBounds(gfx::Rect(501, 0, 500, 1000));
 
-  root_window()->Show();
-
   ui::test::TestEventHandler handler;
   one->AddPreTargetHandler(&handler);
 
@@ -78,6 +78,47 @@ TEST_P(WindowTargeterTest, Basic) {
   one->RemovePreTargetHandler(&handler);
 }
 
+TEST_P(WindowTargeterTest, FindTargetInRootWindow) {
+  WindowTargeter targeter;
+
+  display::Display display =
+      display::Screen::GetScreen()->GetDisplayNearestWindow(root_window());
+  EXPECT_EQ(display.bounds(), root_window()->GetBoundsInScreen());
+  EXPECT_EQ(display.bounds(), gfx::Rect(0, 0, 800, 600));
+
+  // Mouse and touch presses inside the display yield null targets.
+  gfx::Point inside = display.bounds().CenterPoint();
+  ui::MouseEvent mouse1(ui::ET_MOUSE_PRESSED, inside, inside,
+                        ui::EventTimeForNow(), ui::EF_NONE, ui::EF_NONE);
+  ui::TouchEvent touch1(ui::ET_TOUCH_PRESSED, inside, ui::EventTimeForNow(),
+                        ui::PointerDetails());
+  touch1.set_root_location(inside);
+  EXPECT_EQ(nullptr, targeter.FindTargetInRootWindow(root_window(), mouse1));
+  EXPECT_EQ(nullptr, targeter.FindTargetInRootWindow(root_window(), touch1));
+
+  // Touch presses outside the display yields the root window as a target.
+  gfx::Point outside(display.bounds().right() + 10, inside.y());
+  ui::MouseEvent mouse2(ui::ET_MOUSE_PRESSED, outside, outside,
+                        ui::EventTimeForNow(), ui::EF_NONE, ui::EF_NONE);
+  ui::TouchEvent touch2(ui::ET_TOUCH_PRESSED, outside, ui::EventTimeForNow(),
+                        ui::PointerDetails());
+  touch2.set_root_location(outside);
+  EXPECT_EQ(nullptr, targeter.FindTargetInRootWindow(root_window(), mouse2));
+  EXPECT_EQ(root_window(),
+            targeter.FindTargetInRootWindow(root_window(), touch2));
+
+  // Simulate a mus client root (top level app window) with bottom-right bounds.
+  // Touches in the root and display should yield null targets crbug.com/873763.
+  // (mus clients root locations are display coords, not client-root coords)
+  root_window()->SetBounds(gfx::Rect(600, 500, 200, 100));
+  gfx::Point root_touch_coords(199, 99);
+  gfx::Point display_touch_coords(799, 699);
+  ui::TouchEvent touch3(ui::ET_TOUCH_PRESSED, root_touch_coords,
+                        ui::EventTimeForNow(), ui::PointerDetails());
+  touch3.set_root_location(display_touch_coords);
+  EXPECT_EQ(nullptr, targeter.FindTargetInRootWindow(root_window(), touch3));
+}
+
 TEST_P(WindowTargeterTest, ScopedWindowTargeter) {
   test::TestWindowDelegate delegate;
   std::unique_ptr<Window> window(