Implement Chrome OS accessibility features to highlight focus, caret & cursor.

chrome/browser/chromeos/accessibility/accessibility_highlight_manager.cc

+// Copyright (c) 2016 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 "ash/shell.h"
+#include "chrome/browser/chromeos/accessibility/accessibility_highlight_manager.h"
+#include "chrome/browser/chromeos/ui/accessibility_focus_ring_controller.h"
+#include "content/public/browser/focused_node_details.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
+#include "ui/aura/window_tree_host.h"
+
+namespace chromeos {
+
+namespace {
+
+const gfx::Rect& OffscreenRect() {
+  CR_DEFINE_STATIC_LOCAL(const gfx::Rect, r, (INT_MIN, INT_MIN, 0, 0));
+  return r;
+}
+
+const gfx::Point& OffscreenPoint() {
+  CR_DEFINE_STATIC_LOCAL(const gfx::Point, p, (INT_MIN, INT_MIN));
+  return p;
+}
+
+ui::InputMethod* GetInputMethod(aura::Window* root_window) {
+  if (root_window->GetHost())
+    return root_window->GetHost()->GetInputMethod();
+  return nullptr;
+}
+
+}  // namespace
+
+AccessibilityHighlightManager::AccessibilityHighlightManager() {
+  ash::Shell::GetInstance()->AddPreTargetHandler(this);
+  registrar_.Add(this, content::NOTIFICATION_FOCUS_CHANGED_IN_PAGE,
+                 content::NotificationService::AllSources());
+  aura::Window* root_window = ash::Shell::GetPrimaryRootWindow();
+  ui::InputMethod* input_method = GetInputMethod(root_window);
+  input_method->AddObserver(this);
+  focus_rect_ = OffscreenRect();
+  cursor_point_ = OffscreenPoint();
+  caret_point_ = OffscreenPoint();
+}
+
+AccessibilityHighlightManager::~AccessibilityHighlightManager() {
+  // No need to do anything during shutdown
+  if (!ash::Shell::HasInstance())
+    return;
+
+  ash::Shell* shell = ash::Shell::GetInstance();
+  if (shell) {
+    shell->RemovePreTargetHandler(this);
+
+    AccessibilityFocusRingController::GetInstance()->SetFocusRing(
+        std::vector<gfx::Rect>());
+    AccessibilityFocusRingController::GetInstance()->SetCaretRing(
+        OffscreenPoint());
+    AccessibilityFocusRingController::GetInstance()->SetCursorRing(
+        OffscreenPoint());
+
+    aura::Window* root_window = shell->GetPrimaryRootWindow();
+    ui::InputMethod* input_method = GetInputMethod(root_window);
+    input_method->RemoveObserver(this);
+  }
+}
+
+void AccessibilityHighlightManager::HighlightFocus(bool focus) {
+  focus_ = focus;
+
+  std::vector<gfx::Rect> rects;
+  rects.push_back(focus_ ? focus_rect_ : OffscreenRect());
+  AccessibilityFocusRingController::GetInstance()->SetFocusRing(rects);
+}
+
+void AccessibilityHighlightManager::HighlightCursor(bool cursor) {
+  cursor_ = cursor;
+
+  AccessibilityFocusRingController::GetInstance()->SetCursorRing(
+      cursor_ ? cursor_point_ : OffscreenPoint());
+}
+
+void AccessibilityHighlightManager::HighlightCaret(bool caret) {
+  caret_ = caret;
+
+  AccessibilityFocusRingController::GetInstance()->SetCaretRing(
+      caret_ ? caret_point_ : OffscreenPoint());
+}
+
+void AccessibilityHighlightManager::OnMouseEvent(ui::MouseEvent* event) {
+  if (event->type() == ui::ET_MOUSE_MOVED) {
+    cursor_point_ = event->root_location();

[xiyuan, 2016/03/21 22:59:31]

Think we should use event->location() instead of root_location since
AccessibilityFocusRingController expects screen coordinates. 

[dmazzoni, 2016/03/22 04:09:30]

Done. I'll do some more testing with multi-monitor too.

+    AccessibilityFocusRingController::GetInstance()->SetCursorRing(
+        cursor_ ? cursor_point_ : OffscreenPoint());
+  }
+}
+
+void AccessibilityHighlightManager::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  DCHECK_EQ(type, content::NOTIFICATION_FOCUS_CHANGED_IN_PAGE);
+  content::FocusedNodeDetails* node_details =
+      content::Details<content::FocusedNodeDetails>(details).ptr();
+  focus_rect_ = node_details->node_bounds_in_screen;
+
+  if (focus_) {
+    std::vector<gfx::Rect> rects;
+    rects.push_back(focus_rect_);
+    AccessibilityFocusRingController::GetInstance()->SetFocusRing(rects);
+  }
+}
+
+void AccessibilityHighlightManager::OnTextInputStateChanged(
+    const ui::TextInputClient* client) {
+  if (!client || client->GetTextInputType() == ui::TEXT_INPUT_TYPE_NONE) {
+    caret_point_ = OffscreenPoint();
+    if (caret_) {
+      AccessibilityFocusRingController::GetInstance()->SetCaretRing(
+          caret_point_);
+    }
+  }
+}
+
+void AccessibilityHighlightManager::OnCaretBoundsChanged(
+    const ui::TextInputClient* client) {
+  gfx::Rect caret_bounds = client->GetCaretBounds();
+  if (caret_bounds.width() == 0 && caret_bounds.height() == 0)
+    caret_bounds = OffscreenRect();
+  caret_point_ = caret_bounds.CenterPoint();
+
+  if (caret_)
+    AccessibilityFocusRingController::GetInstance()->SetCaretRing(caret_point_);
+}
+
+}  // namespace chromeos