Set a root window for the AuraTestHelper DefaultCaptureClient.

This requires fixing a test that tried to drag between different root
windows while the default capture client was installed, which can't
handle that.  Looking through history, it seems like the whole reason
AuraTestHelper _didn't_ set a root window here originally was because
this test existed, and it was worked around instead of fixed.

TBH, I can't quite remember why I needed to do this at this point,
but it seems more correct regardless.

Bug: none
Change-Id: Ibc14703786d48f3283ec393434781ed02eae5ddb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2117068
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#752831}

ui/aura/DEPS

@@ -27,4 +27,7 @@ specific_include_rules = {
   "native_window_occlusion_tracker_win_interactive_test\.cc": [
     "+mojo/core/embedder/embedder.h",
   ],
+  "window_event_dispatcher_unittest\.cc": [
+    "+ui/wm/core",
+  ],
 }

ui/aura/client/default_capture_client.cc

@@ -21,15 +21,14 @@ Window* global_capture_window_ = nullptr;
 
 DefaultCaptureClient::DefaultCaptureClient(Window* root_window)
     : root_window_(root_window), capture_window_(nullptr) {
-  if (root_window_)
-    SetCaptureClient(root_window_, this);
+  DCHECK(root_window_);
+  SetCaptureClient(root_window_, this);
 }
 
 DefaultCaptureClient::~DefaultCaptureClient() {
   if (global_capture_window_ == capture_window_)
     global_capture_window_ = nullptr;
-  if (root_window_)
-    SetCaptureClient(root_window_, nullptr);
+  SetCaptureClient(root_window_, nullptr);
 }
 
 void DefaultCaptureClient::SetCapture(Window* window) {

ui/aura/client/default_capture_client.h

@@ -15,7 +15,7 @@ namespace client {
 
 class AURA_EXPORT DefaultCaptureClient : public client::CaptureClient {
  public:
-  explicit DefaultCaptureClient(Window* root_window = nullptr);
+  explicit DefaultCaptureClient(Window* root_window);
   ~DefaultCaptureClient() override;
 
  protected:

ui/aura/test/aura_test_helper.cc

@@ -83,7 +83,6 @@ void AuraTestHelper::SetUp(ui::ContextFactory* context_factory) {
   wm_state_ = std::make_unique<wm::WMState>();
   // Needs to be before creating WindowTreeClient.
   focus_client_ = std::make_unique<TestFocusClient>();
-  capture_client_ = std::make_unique<client::DefaultCaptureClient>();
 
   if (!env) {
     // Some tests suites create Env globally rather than per test.
@@ -123,7 +122,8 @@ void AuraTestHelper::SetUp(ui::ContextFactory* context_factory) {
   host_->window()->SetEventTargeter(std::make_unique<WindowTargeter>());
 
   client::SetFocusClient(root_window(), focus_client_.get());
-  client::SetCaptureClient(root_window(), capture_client());
+  capture_client_ =
+      std::make_unique<client::DefaultCaptureClient>(root_window());
   parenting_client_ =
       std::make_unique<TestWindowParentingClient>(root_window());
 
@@ -139,7 +139,7 @@ void AuraTestHelper::TearDown() {
   teardown_called_ = true;
   parenting_client_.reset();
   client::SetFocusClient(root_window(), nullptr);
-  client::SetCaptureClient(root_window(), nullptr);
+  capture_client_.reset();
   host_.reset();
 
   if (display::Screen::GetScreen() == test_screen_.get())
@@ -147,7 +147,6 @@ void AuraTestHelper::TearDown() {
   test_screen_.reset();
 
   focus_client_.reset();
-  capture_client_.reset();
 
   ui::ShutdownInputMethodForTesting();
 

ui/aura/window_event_dispatcher_unittest.cc

@@ -47,6 +47,7 @@
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/transform.h"
 #include "ui/platform_window/platform_window_init_properties.h"
+#include "ui/wm/core/capture_controller.h"
 
 namespace aura {
 namespace {
@@ -2795,40 +2796,49 @@ TEST_F(WindowEventDispatcherTest,
       ui::PlatformWindowInitProperties{gfx::Rect(20, 30, 100, 50)});
   second_host->InitHost();
   second_host->window()->Show();
-  client::SetCaptureClient(second_host->window(),
-                           client::GetCaptureClient(root_window()));
 
-  test::EventCountDelegate delegate;
-  std::unique_ptr<Window> window_first(CreateTestWindowWithDelegate(
-      &delegate, 123, gfx::Rect(20, 10, 10, 20), root_window()));
-  window_first->Show();
-
-  std::unique_ptr<Window> window_second(CreateTestWindowWithDelegate(
-      &delegate, 12, gfx::Rect(10, 10, 20, 30), second_host->window()));
-  window_second->Show();
-
-  window_second->SetCapture();
-  EXPECT_EQ(window_second.get(),
-            client::GetCaptureWindow(root_window()));
-
-  // Send an event to the first host. Make sure it goes to |window_second| in
-  // |second_host| instead (since it has capture).
-  EventFilterRecorder recorder_first;
-  window_first->AddPreTargetHandler(&recorder_first);
-  EventFilterRecorder recorder_second;
-  window_second->AddPreTargetHandler(&recorder_second);
-  const gfx::Point event_location(25, 15);
-  ui::MouseEvent mouse(ui::ET_MOUSE_PRESSED, event_location, event_location,
-                       ui::EventTimeForNow(), ui::EF_LEFT_MOUSE_BUTTON,
-                       ui::EF_LEFT_MOUSE_BUTTON);
-  DispatchEventUsingWindowDispatcher(&mouse);
-  EXPECT_TRUE(recorder_first.events().empty());
-  ASSERT_EQ(1u, recorder_second.events().size());
-  EXPECT_EQ(ui::ET_MOUSE_PRESSED, recorder_second.events()[0]);
-  EXPECT_EQ(event_location.ToString(),
-            recorder_second.mouse_locations()[0].ToString());
-  window_first->RemovePreTargetHandler(&recorder_first);
-  window_second->RemovePreTargetHandler(&recorder_second);
+  // AuraTestBase sets up a DefaultCaptureClient for root_window(), but that
+  // can't deal with capture between different root windows.  Instead we need to
+  // use the wm::CaptureController instance that also exists, which can handle
+  // this situation.  Exchange the capture clients and put the old one back at
+  // the end.
+  client::CaptureClient* const old_capture_client =
+      client::GetCaptureClient(root_window());
+  {
+    wm::ScopedCaptureClient scoped_capture_first(root_window());
+    wm::ScopedCaptureClient scoped_capture_second(second_host->window());
+
+    test::EventCountDelegate delegate;
+    std::unique_ptr<Window> window_first(CreateTestWindowWithDelegate(
+        &delegate, 123, gfx::Rect(20, 10, 10, 20), root_window()));
+    window_first->Show();
+
+    std::unique_ptr<Window> window_second(CreateTestWindowWithDelegate(
+        &delegate, 12, gfx::Rect(10, 10, 20, 30), second_host->window()));
+    window_second->Show();
+
+    window_second->SetCapture();
+
+    // Send an event to the first host. Make sure it goes to |window_second| in
+    // |second_host| instead (since it has capture).
+    EventFilterRecorder recorder_first;
+    window_first->AddPreTargetHandler(&recorder_first);
+    EventFilterRecorder recorder_second;
+    window_second->AddPreTargetHandler(&recorder_second);
+    const gfx::Point event_location(25, 15);
+    ui::MouseEvent mouse(ui::ET_MOUSE_PRESSED, event_location, event_location,
+                         ui::EventTimeForNow(), ui::EF_LEFT_MOUSE_BUTTON,
+                         ui::EF_LEFT_MOUSE_BUTTON);
+    DispatchEventUsingWindowDispatcher(&mouse);
+    EXPECT_TRUE(recorder_first.events().empty());
+    ASSERT_EQ(1u, recorder_second.events().size());
+    EXPECT_EQ(ui::ET_MOUSE_PRESSED, recorder_second.events()[0]);
+    EXPECT_EQ(event_location.ToString(),
+              recorder_second.mouse_locations()[0].ToString());
+    window_first->RemovePreTargetHandler(&recorder_first);
+    window_second->RemovePreTargetHandler(&recorder_second);
+  }
+  client::SetCaptureClient(root_window(), old_capture_client);
 }
 
 class AsyncWindowDelegate : public test::TestWindowDelegate {