Add {Lock,Unlock,Show,Hide}Cursor() to the window manager mojom.

services/ui/ws/cursor_state.cc

+// Copyright 2017 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 "services/ui/ws/cursor_state.h"
+
+#include "base/memory/ptr_util.h"
+#include "services/ui/ws/display.h"
+#include "services/ui/ws/display_manager.h"
+#include "ui/base/cursor/cursor.h"
+
+namespace ui {
+namespace ws {
+
+class CursorState::StateSnapshot {
+ public:
+  StateSnapshot()
+      : cursor_data_(ui::CursorData(ui::CursorType::kNull)), visible_(true) {}
+  StateSnapshot(const StateSnapshot& rhs) = default;
+  ~StateSnapshot() {}
+
+  const base::Optional<ui::CursorData>& global_override_cursor() const {
+    return global_override_cursor_;
+  }
+  void SetGlobalOverrideCursor(const base::Optional<ui::CursorData>& cursor) {
+    global_override_cursor_ = cursor;
+  }
+
+  const ui::CursorData& cursor_data() const { return cursor_data_; }
+  void SetCursorData(const ui::CursorData& data) { cursor_data_ = data; }
+
+  bool visible() const { return visible_; }
+  void set_visible(bool visible) { visible_ = visible; }
+
+ private:
+  // An optional cursor set by the window manager which overrides per-window
+  // requests.
+  base::Optional<ui::CursorData> global_override_cursor_;
+
+  // The last cursor set. Used to track whether we need to change the cursor.
+  ui::CursorData cursor_data_;
+
+  // Whether the cursor is visible.
+  bool visible_;
+};
+
+CursorState::CursorState(DisplayManager* display_manager)
+    : display_manager_(display_manager),
+      current_state_(base::MakeUnique<StateSnapshot>()),
+      state_on_unlock_(base::MakeUnique<StateSnapshot>()) {}
+
+CursorState::~CursorState() {}
+
+void CursorState::SetCurrentWindowCursor(const ui::CursorData& cursor) {
+  if (!state_on_unlock_->cursor_data().IsSameAs(cursor))
+    state_on_unlock_->SetCursorData(cursor);
+
+  if (cursor_lock_count_ == 0 &&
+      !current_state_->cursor_data().IsSameAs(cursor)) {
+    current_state_->SetCursorData(cursor);
+    SetPlatformCursor();
+  }
+}
+
+void CursorState::LockCursor() {
+  cursor_lock_count_++;
+}
+
+void CursorState::UnlockCursor() {
+  cursor_lock_count_--;
+  DCHECK_GE(cursor_lock_count_, 0);
+  if (cursor_lock_count_ > 0)
+    return;
+
+  *current_state_ = *state_on_unlock_;
+  SetPlatformCursor();
+}
+
+void CursorState::SetCursorVisible(bool visible) {
+  state_on_unlock_->set_visible(visible);
+  if (cursor_lock_count_ == 0 &&
+      current_state_->visible() != state_on_unlock_->visible()) {
+    current_state_->set_visible(visible);
+    SetPlatformCursor();
+  }
+}
+
+void CursorState::SetGlobalOverrideCursor(
+    const base::Optional<ui::CursorData>& cursor) {
+  state_on_unlock_->SetGlobalOverrideCursor(cursor);
+  if (cursor_lock_count_ == 0) {
+    current_state_->SetGlobalOverrideCursor(cursor);
+    SetPlatformCursor();
+  }
+}
+
+void CursorState::SetPlatformCursor() {
+  DisplayManager* manager = display_manager_;
+  auto set_on_all = [manager](const ui::CursorData& cursor) {
+    for (Display* display : manager->displays())
+      display->SetNativeCursor(cursor);
+  };
+
+  if (current_state_->visible()) {
+    if (current_state_->global_override_cursor().has_value())
+      set_on_all(current_state_->global_override_cursor().value());
+    else
+      set_on_all(current_state_->cursor_data());
+  } else {
+    set_on_all(ui::CursorData(ui::CursorType::kNone));
+  }
+}
+
+}  // namespace ws
+}  // namespace ui