Reland "[Ash] Simplify AccessibilityControllerImpl to remove duplications"

This reverts commit 812f314f.

Reason for revert: culprit found

Original change's description:
> Revert "[Ash] Simplify AccessibilityControllerImpl to remove duplications"
> 
> This reverts commit 2f2a33d5.
> 
> Reason for revert: <INSERT REASONING HERE>
> It looks like this CL breaks some test case
> https://ci.chromium.org/p/chromium/builders/ci/Linux%20ChromiumOS%20MSan%20Tests/18262?blamelist=1#blamelist-tab
> https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8885542762262570176/+/steps/exo_unittests/0/logs/Deterministic_failure:_All__x2f_SurfaceTest.AcquireFence__x2f_0__status_CRASH_/0
> 
> 
> Original change's description:
> > [Ash] Simplify AccessibilityControllerImpl to remove duplications
> > 
> > AccessibilityControllerImpl had a lot of duplications. Let's fix that.
> > Also, now it controls fullscreen and docked magnifiers. Before that,
> > we have to go AccessibilityDelegate and MagnificationManager to do
> > this.
> > 
> > Change-Id: I6a5d827ded2a88a56eb173fed67e010aa002070d
> > Bug: 1051892
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2050688
> > Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
> > Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
> > Commit-Queue: Anatoliy Potapchuk <apotapchuk@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#751086}
> 
> TBR=xiyuan@chromium.org,dmazzoni@chromium.org,nektar@chromium.org,apotapchuk@chromium.org,burunduk@chromium.org,amraboelkher@google.com
> 
> Change-Id: Ifbd8e25594790d7417af06c84651d3837ad17b5d
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 1051892
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2107028
> Reviewed-by: Nancy Wang <nancylingwang@chromium.org>
> Commit-Queue: Nancy Wang <nancylingwang@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#751181}

TBR=xiyuan@chromium.org,dmazzoni@chromium.org,nektar@chromium.org,apotapchuk@chromium.org,burunduk@chromium.org,amraboelkher@google.com,nancylingwang@chromium.org

Change-Id: If1d69e1f28c1e850c55c038ea7138c75da9ea885
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1051892
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2107545Reviewed-by: Anatoliy Potapchuk <apotapchuk@chromium.org>
Commit-Queue: Anatoliy Potapchuk <apotapchuk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#751188}

ash/accessibility/accessibility_controller_impl.h

@@ -13,6 +13,7 @@
 #include "ash/public/cpp/tablet_mode_observer.h"
 #include "ash/session/session_observer.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/time/time.h"
 
@@ -28,6 +29,7 @@ enum class Gesture;
 
 namespace gfx {
 class Point;
+struct VectorIcon;
 }  // namespace gfx
 
 namespace ash {
@@ -50,6 +52,101 @@ class ASH_EXPORT AccessibilityControllerImpl : public AccessibilityController,
                                                public SessionObserver,
                                                public TabletModeObserver {
  public:
+  enum FeatureType {
+    kAutoclick = 0,
+    kCaretHighlight,
+    KCursorHighlight,
+    kDictation,
+    kFocusHighlight,
+    kFullscreenMagnifier,
+    kDockedMagnifier,
+    kHighContrast,
+    kLargeCursor,
+    kMonoAudio,
+    kSpokenFeedback,
+    kSelectToSpeak,
+    kStickyKeys,
+    kSwitchAccess,
+    kVirtualKeyboard,
+
+    kFeatureCount,
+    kNoConflictingFeature
+  };
+
+  // Common interface for all features.
+  class Feature {
+   public:
+    Feature(FeatureType type,
+            const std::string& pref_name,
+            const gfx::VectorIcon* icon,
+            AccessibilityControllerImpl* controller);
+    Feature(const Feature&) = delete;
+    Feature& operator=(Feature const&) = delete;
+    virtual ~Feature();
+
+    FeatureType type() const { return type_; }
+    // Tries to set the feature to |enabled| by setting the user pref.
+    // Setting feature to be enabled can fail in following conditions:
+    // - there is a higher priority pref(managed), which overrides this value.
+    // - there is an other feature, which conflicts with the current one.
+    virtual void SetEnabled(bool enabled);
+    bool enabled() const { return enabled_; }
+    bool IsVisibleInTray() const;
+    bool IsEnterpriseIconVisible() const;
+    const std::string& pref_name() const { return pref_name_; }
+    const gfx::VectorIcon& icon() const;
+
+    void UpdateFromPref();
+    void SetConflictingFeature(FeatureType feature);
+
+   protected:
+    FeatureType type_;
+    // Some features cannot be enabled while others are on. When a conflicting
+    // feature is enabled, we cannot enable current feature.
+    FeatureType conflicting_feature_ = FeatureType::kNoConflictingFeature;
+    bool enabled_;
+    const std::string pref_name_;
+    const gfx::VectorIcon* icon_;
+    AccessibilityControllerImpl* owner_;
+  };
+
+  // Helper struct to store information about a11y dialog -- pref name, resource
+  // ids for title and body. Also stores the information whether this dialog is
+  // mandatory for every SetEnabled call.
+  struct Dialog {
+    std::string pref_name;
+    int title_resource_id;
+    int body_resource_id;
+    // Whether this dialog should be shown on every SetEnabled action.
+    bool mandatory;
+  };
+
+  // Some features have confirmation dialog associated with them.
+  // Dialog can be applied for all SetEnabled() actions, or only to ones
+  // associated with accelerators.
+  class FeatureWithDialog : public Feature {
+   public:
+    FeatureWithDialog(FeatureType type,
+                      const std::string& pref_name,
+                      const gfx::VectorIcon* icon,
+                      const Dialog& dialog,
+                      AccessibilityControllerImpl* controller);
+    ~FeatureWithDialog() override;
+
+    // Tries to set the feature enabled, if its dialog is mandatory, shows the
+    // dailog for the first time feature is enabled.
+    void SetEnabled(bool enabled) override;
+    // If the dialog have not been accepted, we show it. When it is accepted, we
+    // call SetEnabled() and invoke |completion_callback|.
+    void SetEnabledWithDialog(bool enabled,
+                              base::OnceClosure completion_callback);
+    void SetDialogAccepted();
+    bool WasDialogAccepted() const;
+
+   private:
+    Dialog dialog_;
+  };
+
   AccessibilityControllerImpl();
   ~AccessibilityControllerImpl() override;
 
@@ -61,6 +158,13 @@ class ASH_EXPORT AccessibilityControllerImpl : public AccessibilityController,
   void AddObserver(AccessibilityObserver* observer);
   void RemoveObserver(AccessibilityObserver* observer);
 
+  Feature& GetFeature(FeatureType feature) const;
+
+  // Getters for the corresponding features.
+  Feature& autoclick() const;
+  Feature& caret_highlight() const;
+  Feature& cursor_highlight() const;
+
   // The following functions read and write to their associated preference.
   // These values are then used to determine whether the accelerator
   // confirmation dialog for the respective preference has been accepted before.
@@ -76,7 +180,7 @@ class ASH_EXPORT AccessibilityControllerImpl : public AccessibilityController,
   bool HasDisplayRotationAcceleratorDialogBeenAccepted() const;
 
   void SetAutoclickEnabled(bool enabled);
-  bool autoclick_enabled() const { return autoclick_enabled_; }
+  bool autoclick_enabled() const { return autoclick().enabled(); }
   bool IsAutoclickSettingVisibleInTray();
   bool IsEnterpriseIconVisibleForAutoclick();
 
@@ -92,12 +196,12 @@ class ASH_EXPORT AccessibilityControllerImpl : public AccessibilityController,
   void UpdateAutoclickMenuBoundsIfNeeded();
 
   void SetCaretHighlightEnabled(bool enabled);
-  bool caret_highlight_enabled() const { return caret_highlight_enabled_; }
+  bool caret_highlight_enabled() const { return caret_highlight().enabled(); }
   bool IsCaretHighlightSettingVisibleInTray();
   bool IsEnterpriseIconVisibleForCaretHighlight();
 
   void SetCursorHighlightEnabled(bool enabled);
-  bool cursor_highlight_enabled() const { return cursor_highlight_enabled_; }
+  bool cursor_highlight_enabled() const { return cursor_highlight().enabled(); }
   bool IsCursorHighlightSettingVisibleInTray();
   bool IsEnterpriseIconVisibleForCursorHighlight();
 
@@ -268,6 +372,12 @@ class ASH_EXPORT AccessibilityControllerImpl : public AccessibilityController,
   SwitchAccessEventHandler* GetSwitchAccessEventHandlerForTest();
 
  private:
+  // Populate |features_| with the feature of the correct type.
+  void CreateAccessibilityFeatures();
+
+  // Propagates the state of |feature| according to |feature->enabled()|.
+  void OnFeatureChanged(FeatureType feature);
+
   // TabletModeObserver:
   void OnTabletModeStarted() override;
   void OnTabletModeEnded() override;
@@ -276,15 +386,15 @@ class ASH_EXPORT AccessibilityControllerImpl : public AccessibilityController,
   // initial settings.
   void ObservePrefs(PrefService* prefs);
 
-  void UpdateAutoclickFromPref();
+  // Updates the actual feature status based on the prefs value.
+  void UpdateFeatureFromPref(FeatureType feature);
+
   void UpdateAutoclickDelayFromPref();
   void UpdateAutoclickEventTypeFromPref();
   void UpdateAutoclickRevertToLeftClickFromPref();
   void UpdateAutoclickStabilizePositionFromPref();
   void UpdateAutoclickMovementThresholdFromPref();
   void UpdateAutoclickMenuPositionFromPref();
-  void UpdateCaretHighlightFromPref();
-  void UpdateCursorHighlightFromPref();
   void UpdateDictationFromPref();
   void UpdateFocusHighlightFromPref();
   void UpdateHighContrastFromPref();
@@ -306,19 +416,12 @@ class ASH_EXPORT AccessibilityControllerImpl : public AccessibilityController,
   void MaybeCreateSelectToSpeakEventHandler();
   void MaybeCreateSwitchAccessEventHandler();
 
-  // The pref service of the currently active user or the signin profile before
-  // user logs in. Can be null in ash_unittests.
-  PrefService* active_user_prefs_ = nullptr;
-
-  std::unique_ptr<PrefChangeRegistrar> pref_change_registrar_;
-
   // Client interface in chrome browser.
   AccessibilityControllerClient* client_ = nullptr;
 
-  bool autoclick_enabled_ = false;
+  std::unique_ptr<Feature> features_[kFeatureCount];
+
   base::TimeDelta autoclick_delay_;
-  bool caret_highlight_enabled_ = false;
-  bool cursor_highlight_enabled_ = false;
   bool dictation_enabled_ = false;
   bool focus_highlight_enabled_ = false;
   bool high_contrast_enabled_ = false;
@@ -355,6 +458,15 @@ class ASH_EXPORT AccessibilityControllerImpl : public AccessibilityController,
 
   base::ObserverList<AccessibilityObserver> observers_;
 
+  // The pref service of the currently active user or the signin profile before
+  // user logs in. Can be null in ash_unittests.
+  PrefService* active_user_prefs_ = nullptr;
+  // This has to be the first one to be destroyed so we don't get updates about
+  // any prefs during destruction.
+  std::unique_ptr<PrefChangeRegistrar> pref_change_registrar_;
+
+  base::WeakPtrFactory<AccessibilityControllerImpl> weak_ptr_factory_{this};
+
   DISALLOW_COPY_AND_ASSIGN(AccessibilityControllerImpl);
 };