Test that a kNone ui::Cursor works as expected

The cursor type mojom::CursorType::kNone is used to hide the cursor.
Therefore, CursorLoader::SetPlatformCursor() should create an invisible
platform cursor for that type.

This CL adds a test that checks that that's the case for the different
implementations of platform cursors.

Bug: 1139157
Change-Id: If9cde827f820e6420d0298dcdf6df3b1dbaafd49
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2485101Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Henrique Ferreiro <hferreiro@igalia.com>
Cr-Commit-Position: refs/heads/master@{#819316}

ui/base/cursor/BUILD.gn

@@ -106,26 +106,39 @@ if (use_aura) {
 source_set("unittests") {
   testonly = true
   sources = []
-  deps = [ "//testing/gtest" ]
+  deps = [
+    ":cursor_base",
+    "//testing/gtest",
+    "//ui/base/cursor/mojom:cursor_type",
+  ]
 
   if (!is_ios) {
     sources += [ "cursor_unittest.cc" ]
     deps += [
-      ":cursor_base",
       "//skia",
-      "//ui/base/cursor/mojom:cursor_type",
       "//ui/gfx:geometry_skia",
       "//ui/gfx/geometry",
     ]
   }
 
   if (use_aura) {
-    sources += [ "cursor_util_unittest.cc" ]
+    sources += [
+      "cursor_loader_unittest.cc",
+      "cursor_util_unittest.cc",
+    ]
     deps += [
       ":cursor",
       "//skia",
       "//ui/gfx/geometry",
     ]
+
+    if (use_x11) {
+      deps += [
+        "//skia",
+        "//ui/base/x",
+        "//ui/gfx/geometry",
+      ]
+    }
   }
 
   if (use_ozone) {
@@ -133,7 +146,6 @@ source_set("unittests") {
     deps += [
       ":cursor",
       "//base",
-      "//ui/base/cursor/mojom:cursor_type",
     ]
   }
 }

ui/base/cursor/cursor_loader.h

@@ -5,6 +5,8 @@
 #ifndef UI_BASE_CURSOR_CURSOR_LOADER_H_
 #define UI_BASE_CURSOR_CURSOR_LOADER_H_
 
+#include <memory>
+
 #include "base/component_export.h"
 #include "base/macros.h"
 #include "ui/base/cursor/mojom/cursor_type.mojom-forward.h"
@@ -60,7 +62,7 @@ class COMPONENT_EXPORT(UI_BASE_CURSOR) CursorLoader {
   virtual void SetPlatformCursor(gfx::NativeCursor* cursor) = 0;
 
   // Creates a CursorLoader.
-  static CursorLoader* Create();
+  static std::unique_ptr<CursorLoader> Create();
 
  private:
   // The current scale of the mouse cursor icon.

ui/base/cursor/cursor_loader_ozone.cc

@@ -4,6 +4,7 @@
 
 #include "ui/base/cursor/cursor_loader_ozone.h"
 
+#include <memory>
 #include <vector>
 
 #include "ui/base/cursor/cursor_factory.h"
@@ -98,8 +99,8 @@ PlatformCursor CursorLoaderOzone::CreateFallbackCursor(mojom::CursorType type) {
   return nullptr;
 }
 
-CursorLoader* CursorLoader::Create() {
-  return new CursorLoaderOzone();
+std::unique_ptr<CursorLoader> CursorLoader::Create() {
+  return std::make_unique<CursorLoaderOzone>();
 }
 
 }  // namespace ui

ui/base/cursor/cursor_loader_unittest.cc

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/base/cursor/cursor_loader.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/base/cursor/cursor.h"
+#include "ui/base/cursor/mojom/cursor_type.mojom-shared.h"
+
+#if defined(USE_OZONE)
+#include "ui/base/cursor/ozone/bitmap_cursor_factory_ozone.h"
+#endif
+
+#if defined(USE_X11)
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/base/x/x11_cursor_factory.h"  // nogncheck
+#include "ui/gfx/geometry/point.h"
+#endif
+
+namespace ui {
+
+namespace {
+
+PlatformCursor LoadInvisibleCursor() {
+  auto cursor_loader = CursorLoader::Create();
+  Cursor cursor(mojom::CursorType::kNone);
+  cursor_loader->SetPlatformCursor(&cursor);
+  return cursor.platform();
+}
+
+}  // namespace
+
+#if !defined(USE_X11)
+TEST(CursorLoaderTest, InvisibleCursorOnNotX11) {
+#if defined(USE_OZONE)
+  BitmapCursorFactoryOzone cursor_factory;
+#endif
+  EXPECT_EQ(LoadInvisibleCursor(), nullptr);
+}
+#endif
+
+#if defined(USE_X11)
+TEST(CursorLoaderTest, InvisibleCursorOnX11) {
+  X11CursorFactory cursor_factory;
+  // Building an image cursor with an invalid SkBitmap should return the
+  // invisible cursor in X11.
+  auto* invisible_cursor =
+      cursor_factory.CreateImageCursor(SkBitmap(), gfx::Point());
+  EXPECT_EQ(LoadInvisibleCursor(), invisible_cursor);
+
+  // Release our refcount on the cursor
+  cursor_factory.UnrefImageCursor(invisible_cursor);
+}
+#endif
+
+}  // namespace ui

ui/base/cursor/cursor_loader_win.cc

@@ -6,6 +6,8 @@
 
 #include <windows.h>
 
+#include <memory>
+
 #include "base/lazy_instance.h"
 #include "base/notreached.h"
 #include "ui/base/cursor/cursor.h"
@@ -122,8 +124,8 @@ const wchar_t* GetCursorId(gfx::NativeCursor native_cursor) {
 
 }  // namespace
 
-CursorLoader* CursorLoader::Create() {
-  return new CursorLoaderWin;
+std::unique_ptr<CursorLoader> CursorLoader::Create() {
+  return std::make_unique<CursorLoaderWin>();
 }
 
 CursorLoaderWin::CursorLoaderWin() {