[ozone/wayland] Implement GetDisplayMatching.

Use display::FindDisplayWithBiggestIntersection to find
a display with biggest intersection with the specified rect.

If no display found, return a default display with invalid
id.

Bug: 875161
Change-Id: I585c3c23daba8ff0c2c58bc94f074fff6783a2d7
Reviewed-on: https://chromium-review.googlesource.com/c/1430002
Commit-Queue: Maksim Sisov <msisov@igalia.com>
Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Cr-Commit-Position: refs/heads/master@{#626487}

ui/ozone/platform/wayland/wayland_screen.cc

@@ -129,9 +129,12 @@ display::Display WaylandScreen::GetDisplayNearestPoint(
 
 display::Display WaylandScreen::GetDisplayMatching(
     const gfx::Rect& match_rect) const {
-  // TODO(msisov): https://crbug.com/890272
-  NOTIMPLEMENTED_LOG_ONCE();
-  return GetPrimaryDisplay();
+  const display::Display* display_matching =
+      display::FindDisplayWithBiggestIntersection(display_list_.displays(),
+                                                  match_rect);
+  if (!display_matching)
+    return display::Display();
+  return *display_matching;
 }
 
 void WaylandScreen::AddObserver(display::DisplayObserver* observer) {

ui/ozone/platform/wayland/wayland_screen_unittest.cc

@@ -281,6 +281,76 @@ TEST_P(WaylandScreenTest, GetAcceleratedWidgetAtScreenPoint) {
   window_->set_pointer_focus(false);
 }
 
+TEST_P(WaylandScreenTest, GetDisplayMatching) {
+  TestDisplayObserver observer;
+  platform_screen_->AddObserver(&observer);
+
+  const display::Display primary_display =
+      platform_screen_->GetPrimaryDisplay();
+
+  wl::MockOutput* output2 = server_.CreateAndInitializeOutput();
+
+  Sync();
+
+  // Place it on the right side of the primary display.
+  const gfx::Rect output2_rect =
+      gfx::Rect(primary_display.bounds().width(), 0, 1024, 768);
+  UpdateOutputGeometry(output2->resource(), output2_rect);
+
+  Sync();
+
+  const display::Display second_display = observer.GetDisplay();
+  EXPECT_EQ(second_display.bounds(), output2_rect);
+
+  // We have two displays: display1(0:0,1024x768) and display2(1024:0,1024x768).
+  EXPECT_EQ(
+      primary_display.id(),
+      platform_screen_->GetDisplayMatching(gfx::Rect(0, 0, 100, 100)).id());
+  EXPECT_EQ(
+      second_display.id(),
+      platform_screen_->GetDisplayMatching(gfx::Rect(1024, 0, 10, 10)).id());
+
+  // More pixels on second display.
+  EXPECT_EQ(
+      second_display.id(),
+      platform_screen_->GetDisplayMatching(gfx::Rect(1020, 0, 10, 10)).id());
+
+  // More pixels on first display.
+  EXPECT_EQ(
+      primary_display.id(),
+      platform_screen_->GetDisplayMatching(gfx::Rect(1018, 0, 10, 10)).id());
+
+  // Half pixels on second and half on primary.
+  EXPECT_EQ(
+      primary_display.id(),
+      platform_screen_->GetDisplayMatching(gfx::Rect(1019, 0, 10, 10)).id());
+
+  // Place second display 700 pixels below along y axis (1024:700,1024x768)
+  UpdateOutputGeometry(
+      output2->resource(),
+      gfx::Rect(gfx::Point(output2_rect.x(), output2_rect.y() + 700),
+                output2_rect.size()));
+
+  Sync();
+
+  // The match rect is located outside the displays.
+  EXPECT_EQ(
+      display::kInvalidDisplayId,
+      platform_screen_->GetDisplayMatching(gfx::Rect(1024, 0, 10, 10)).id());
+
+  // At least some of the pixels are located on the display.
+  EXPECT_EQ(
+      primary_display.id(),
+      platform_screen_->GetDisplayMatching(gfx::Rect(1023, 0, 10, 10)).id());
+
+  // Most of pixels are located on second display.
+  EXPECT_EQ(
+      second_display.id(),
+      platform_screen_->GetDisplayMatching(gfx::Rect(1023, 695, 10, 10)).id());
+
+  platform_screen_->RemoveObserver(&observer);
+}
+
 INSTANTIATE_TEST_SUITE_P(XdgVersionV5Test,
                          WaylandScreenTest,
                          ::testing::Values(kXdgShellV5));