Add 5 experimental accessibility features on Chrome OS.

This just adds the boilerplate for five new accessibility features and hides
them behind a flag. All five have been prototyped and are ready for
implementation.

The first three are related, they just provide visual highlighting to
help low-vision users keep track of things on the screen:
* Caret highlight
* Cursor highlight
* Focus highlight

Hold down a key and click or drag to speak any visible text on screen
* Select to speak

Control the whole computer with a single switch (for motor impaired users)
* Switch access

For now, there's no need to put these in the tray. They can graduate to the
tray when they launch.

BUG=314889,593887,593885

Review URL: https://codereview.chromium.org/1785833002

Cr-Commit-Position: refs/heads/master@{#381353}

3 files changed, 94 insertions, 18 deletions

diff --git a/ash/accessibility_delegate.h b/ash/accessibility_delegate.h
index cb821c8..f702c2a 100644
--- a/ash/accessibility_delegate.h
+++ b/ash/accessibility_delegate.h
@@ -59,6 +59,36 @@ class ASH_EXPORT AccessibilityDelegate {
   // Returns if the a11y virtual keyboard is enabled.
   virtual bool IsVirtualKeyboardEnabled() const = 0;
 
+  // Invoked to enable or disable caret highlighting.
+  virtual void SetCaretHighlightEnabled(bool enabled) = 0;
+
+  // Returns if caret highlighting is enabled.
+  virtual bool IsCaretHighlightEnabled() const = 0;
+
+  // Invoked to enable or disable cursor highlighting.
+  virtual void SetCursorHighlightEnabled(bool enabled) = 0;
+
+  // Returns if cursor highlighting is enabled.
+  virtual bool IsCursorHighlightEnabled() const = 0;
+
+  // Invoked to enable or disable focus highlighting.
+  virtual void SetFocusHighlightEnabled(bool enabled) = 0;
+
+  // Returns if focus highlighting is enabled.
+  virtual bool IsFocusHighlightEnabled() const = 0;
+
+  // Invoked to enable or disable select-to-speak.
+  virtual void SetSelectToSpeakEnabled(bool enabled) = 0;
+
+  // Returns if select-to-speak is enabled.
+  virtual bool IsSelectToSpeakEnabled() const = 0;
+
+  // Invoked to enable or disable switch access.
+  virtual void SetSwitchAccessEnabled(bool enabled) = 0;
+
+  // Returns if switch access is enabled.
+  virtual bool IsSwitchAccessEnabled() const = 0;
+
   // Returns true when the accessibility menu should be shown.
   virtual bool ShouldShowAccessibilityMenu() const = 0;
 
diff --git a/ash/default_accessibility_delegate.cc b/ash/default_accessibility_delegate.cc
index f337a2e..402e5b5 100644
--- a/ash/default_accessibility_delegate.cc
+++ b/ash/default_accessibility_delegate.cc
@@ -8,16 +8,7 @@
 
 namespace ash {
 
-DefaultAccessibilityDelegate::DefaultAccessibilityDelegate()
-    : spoken_feedback_enabled_(false),
-      high_contrast_enabled_(false),
-      screen_magnifier_enabled_(false),
-      screen_magnifier_type_(ui::kDefaultMagnifierType),
-      large_cursor_enabled_(false),
-      autoclick_enabled_(false),
-      virtual_keyboard_enabled_(false),
-      accessibility_alert_(ui::A11Y_ALERT_NONE) {
-}
+DefaultAccessibilityDelegate::DefaultAccessibilityDelegate() {}
 
 DefaultAccessibilityDelegate::~DefaultAccessibilityDelegate() {}
 
@@ -73,6 +64,46 @@ bool DefaultAccessibilityDelegate::IsVirtualKeyboardEnabled() const {
   return virtual_keyboard_enabled_;
 }
 
+void DefaultAccessibilityDelegate::SetCaretHighlightEnabled(bool enabled) {
+  caret_highlight_enabled_ = enabled;
+}
+
+bool DefaultAccessibilityDelegate::IsCaretHighlightEnabled() const {
+  return caret_highlight_enabled_;
+}
+
+void DefaultAccessibilityDelegate::SetCursorHighlightEnabled(bool enabled) {
+  cursor_highlight_enabled_ = enabled;
+}
+
+bool DefaultAccessibilityDelegate::IsCursorHighlightEnabled() const {
+  return cursor_highlight_enabled_;
+}
+
+void DefaultAccessibilityDelegate::SetFocusHighlightEnabled(bool enabled) {
+  focus_highligh_enabled_ = enabled;
+}
+
+bool DefaultAccessibilityDelegate::IsFocusHighlightEnabled() const {
+  return focus_highligh_enabled_;
+}
+
+void DefaultAccessibilityDelegate::SetSelectToSpeakEnabled(bool enabled) {
+  select_to_speak_enabled_ = enabled;
+}
+
+bool DefaultAccessibilityDelegate::IsSelectToSpeakEnabled() const {
+  return select_to_speak_enabled_;
+}
+
+void DefaultAccessibilityDelegate::SetSwitchAccessEnabled(bool enabled) {
+  switch_access_enabled_ = enabled;
+}
+
+bool DefaultAccessibilityDelegate::IsSwitchAccessEnabled() const {
+  return switch_access_enabled_;
+}
+
 bool DefaultAccessibilityDelegate::ShouldShowAccessibilityMenu() const {
   return spoken_feedback_enabled_ ||
          high_contrast_enabled_ ||
diff --git a/ash/default_accessibility_delegate.h b/ash/default_accessibility_delegate.h
index e973f56..986b13bb 100644
--- a/ash/default_accessibility_delegate.h
+++ b/ash/default_accessibility_delegate.h
@@ -30,6 +30,16 @@ class ASH_EXPORT DefaultAccessibilityDelegate : public AccessibilityDelegate {
   bool IsAutoclickEnabled() const override;
   void SetVirtualKeyboardEnabled(bool enabled) override;
   bool IsVirtualKeyboardEnabled() const override;
+  void SetCaretHighlightEnabled(bool enabled) override;
+  bool IsCaretHighlightEnabled() const override;
+  void SetCursorHighlightEnabled(bool enabled) override;
+  bool IsCursorHighlightEnabled() const override;
+  void SetFocusHighlightEnabled(bool enabled) override;
+  bool IsFocusHighlightEnabled() const override;
+  void SetSelectToSpeakEnabled(bool enabled) override;
+  bool IsSelectToSpeakEnabled() const override;
+  void SetSwitchAccessEnabled(bool enabled) override;
+  bool IsSwitchAccessEnabled() const override;
   bool ShouldShowAccessibilityMenu() const override;
   bool IsBrailleDisplayConnected() const override;
   void SilenceSpokenFeedback() const override;
@@ -43,14 +53,19 @@ class ASH_EXPORT DefaultAccessibilityDelegate : public AccessibilityDelegate {
   base::TimeDelta PlayShutdownSound() const override;
 
  private:
-  bool spoken_feedback_enabled_;
-  bool high_contrast_enabled_;
-  bool screen_magnifier_enabled_;
-  ui::MagnifierType screen_magnifier_type_;
-  bool large_cursor_enabled_;
-  bool autoclick_enabled_;
-  bool virtual_keyboard_enabled_;
-  ui::AccessibilityAlert accessibility_alert_;
+  bool spoken_feedback_enabled_ = false;
+  bool high_contrast_enabled_ = false;
+  bool screen_magnifier_enabled_ = false;
+  ui::MagnifierType screen_magnifier_type_ = ui::kDefaultMagnifierType;
+  bool large_cursor_enabled_ = false;
+  bool autoclick_enabled_ = false;
+  bool virtual_keyboard_enabled_ = false;
+  bool caret_highlight_enabled_ = false;
+  bool cursor_highlight_enabled_ = false;
+  bool focus_highligh_enabled_ = false;
+  bool select_to_speak_enabled_ = false;
+  bool switch_access_enabled_ = false;
+  ui::AccessibilityAlert accessibility_alert_ = ui::A11Y_ALERT_NONE;
   DISALLOW_COPY_AND_ASSIGN(DefaultAccessibilityDelegate);
 };