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

@@ -21,14 +21,13 @@ Window* global_capture_window_ = nullptr;
 
 DefaultCaptureClient::DefaultCaptureClient(Window* root_window)
     : root_window_(root_window), capture_window_(nullptr) {
-  if (root_window_)
+  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);
 }
 

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 {
@@ -2795,8 +2796,17 @@ 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()));
+
+  // 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(
@@ -2808,8 +2818,6 @@ TEST_F(WindowEventDispatcherTest,
     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).
@@ -2829,6 +2837,8 @@ TEST_F(WindowEventDispatcherTest,
               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 {