chromeos: makes ServerWindow install pre-target handler using kDefault

Using kSystem means it conflicts with other system level landers, such as
the laser pointer.

BUG=867483
TEST=covered by tests

Change-Id: I40581e6ae8716e333d1e64ecd2ae8ebbcbf1936d
Reviewed-on: https://chromium-review.googlesource.com/1151546Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578438}

ash/laser/laser_pointer_controller_unittest.cc

@@ -9,6 +9,7 @@
 #include "ash/public/cpp/config.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
+#include "services/ui/ws2/server_window.h"
 #include "ui/events/test/event_generator.h"
 
 namespace ash {
@@ -154,4 +155,25 @@ TEST_F(LaserPointerControllerTest, LaserPointerPrediction) {
             controller_test_api_->predicted_laser_points().GetNumberOfPoints());
 }
 
+// Test to laser pointer is shown for touches over a remote app.
+TEST_F(LaserPointerControllerTest, LaserPointerWorksWithRemoteApp) {
+  std::unique_ptr<aura::Window> window =
+      CreateTestWindow(gfx::Rect(50, 50, 100, 100));
+  ui::ws2::ServerWindow* server_window =
+      ui::ws2::ServerWindow::GetMayBeNull(window.get());
+  ASSERT_TRUE(server_window);
+  // Setting the client area triggers slightly different logic.
+  server_window->SetClientArea(gfx::Insets(10), std::vector<gfx::Rect>());
+
+  // The laser pointer mode only works with stylus.
+  ui::test::EventGenerator* event_generator = GetEventGenerator();
+  event_generator->EnterPenPointerMode();
+  controller_test_api_->SetEnabled(true);
+
+  event_generator->MoveTouch(gfx::Point(100, 100));
+  EXPECT_FALSE(controller_test_api_->IsShowingLaserPointer());
+  event_generator->PressTouch();
+  EXPECT_TRUE(controller_test_api_->IsShowingLaserPointer());
+}
+
 }  // namespace ash

ash/test/ash_test_base.h

@@ -104,8 +104,8 @@ class AshTestBase : public testing::Test {
   // |bounds_in_screen|. |shell_window_id| is the shell window id to give to
   // the new window.
   //
-  // In classic mode this simulates creating a window as a client of Ash would.
-  // That is, it goes through the WindowService.
+  // This function simulates creating a window as a client of Ash would. That
+  // is, it goes through the WindowService.
   //
   // TODO(sky): convert existing CreateTestWindow() functions into this one.
   std::unique_ptr<aura::Window> CreateTestWindow(

services/ui/ws2/BUILD.gn

@@ -13,6 +13,9 @@ component("lib") {
   friend = [
     ":tests",
     ":test_support",
+
+    # It's ok for tests to depend upon private code.
+    "//ash:ash_unittests",
   ]
   public = [
     "gpu_interface_provider.h",

services/ui/ws2/server_window.cc

@@ -126,7 +126,9 @@ class ServerWindowEventHandler : public ui::EventHandler {
  public:
   explicit ServerWindowEventHandler(ServerWindow* server_window)
       : server_window_(server_window) {
-    window()->AddPreTargetHandler(this, ui::EventTarget::Priority::kSystem);
+    // Use |kDefault| so as not to conflict with other important pre-target
+    // handlers (such as laser pointer).
+    window()->AddPreTargetHandler(this, ui::EventTarget::Priority::kDefault);
   }
   ~ServerWindowEventHandler() override {
     window()->RemovePreTargetHandler(this);