Implement touch exploration touch typing

ash/ash_touch_exploration_manager_chromeos.cc

 // Copyright 2014 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/ash_touch_exploration_manager_chromeos.h"
 
 #include "ash/accessibility_delegate.h"
 #include "ash/root_window_controller.h"
 #include "ash/shared/app_types.h"
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray_notifier.h"
 #include "ash/wm/window_util.h"
 #include "ash/wm_window.h"
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "chromeos/audio/chromeos_sounds.h"
 #include "chromeos/audio/cras_audio_handler.h"
 #include "chromeos/chromeos_switches.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/chromeos/touch_exploration_controller.h"
+#include "ui/keyboard/keyboard_controller.h"
 #include "ui/wm/public/activation_client.h"
 
 namespace ash {
 
 AshTouchExplorationManager::AshTouchExplorationManager(
     RootWindowController* root_window_controller)
     : root_window_controller_(root_window_controller),
       audio_handler_(chromeos::CrasAudioHandler::Get()),
       enable_chromevox_arc_support_(
           base::CommandLine::ForCurrentProcess()->HasSwitch(
               chromeos::switches::kEnableChromeVoxArcSupport)) {
   Shell::Get()->system_tray_notifier()->AddAccessibilityObserver(this);
   Shell::Get()->activation_client()->AddObserver(this);
   display::Screen::GetScreen()->AddObserver(this);
   UpdateTouchExplorationState();
 }
 
 AshTouchExplorationManager::~AshTouchExplorationManager() {
+  keyboard::KeyboardController* keyboard_controller =
+      keyboard::KeyboardController::GetInstance();
+  if (keyboard_controller)
+    keyboard_controller->RemoveObserver(this);

[Daniel Erat, 2017/05/26 16:33:38]

yes, please use ScopedObserver. this is still wrong, as the observer is removed
in the d'tor but not added in the c'tor, i.e. you'll remove without having added
earlier if UpdateTouchExplorationState isn't called before destruction.

[David Tseng, 2017/05/26 21:13:47]

Sorry, I must be mistaken, but removing if not previously added is a no-op,
right, so why does this matter?

The larger issue here is that the keyboard controller gets re-initialized on
session state changed, so though the keyboard controller looks like a singleton,
it's not and AshTouchExplorationManager has a slightly longer lifetime than
KeyboardControllers.

It's not entirely clear to me what the relationship between
AshTouchExplorationManager (which is owned by RootWindowController) and
KeyboardController should be.

[Daniel Erat, 2017/05/26 21:37:23]

it's standard practice in chrome to keep track of whether you've added an
observer and remove it iff it's been added. you can't double-add, for instance:
https://chromium.googlesource.com/chromium/src/+/master/base/observer_list.h#276

i didn't realize that the KeyboardController is reinitialized. do you have some
way to register to be notified when it's destroyed? (does it have an
OnDestroying() method in its observer class?)

[David Tseng, 2017/05/30 16:45:29]

Sort of (indirectly through ShellObserver). There is some precedence for an
object wanting to observe keyboard changes (see ShelfLayoutManager). I've added
similar support in AshTouchExplorationManager.

   SystemTrayNotifier* system_tray_notifier =
       Shell::Get()->system_tray_notifier();
   if (system_tray_notifier)
     system_tray_notifier->RemoveAccessibilityObserver(this);
   Shell::Get()->activation_client()->RemoveObserver(this);
   display::Screen::GetScreen()->RemoveObserver(this);
 }
 
 void AshTouchExplorationManager::OnAccessibilityModeChanged(
     AccessibilityNotificationVisibility notify) {
@@ skipping 86 matching lines @@
 }
 
 void AshTouchExplorationManager::SetTouchAccessibilityAnchorPoint(
     const gfx::Point& anchor_point) {
   if (touch_exploration_controller_) {
     touch_exploration_controller_->SetTouchAccessibilityAnchorPoint(
         anchor_point);
   }
 }
 
+void AshTouchExplorationManager::OnKeyboardBoundsChanging(
+    const gfx::Rect& new_bounds) {
+  UpdateTouchExplorationState();
+}
+
+void AshTouchExplorationManager::OnKeyboardClosed() {
+  UpdateTouchExplorationState();
+}
+
 void AshTouchExplorationManager::UpdateTouchExplorationState() {
   // See crbug.com/603745 for more details.
   const bool pass_through_surface =
       wm::GetActiveWindow() &&
       wm::GetActiveWindow()->GetProperty(aura::client::kAppType) ==
           static_cast<int>(ash::AppType::ARC_APP) &&
       !enable_chromevox_arc_support_;
 
   const bool spoken_feedback_enabled =
       Shell::Get()->accessibility_delegate()->IsSpokenFeedbackEnabled();
@@ skipping 14 matching lines @@
     if (pass_through_surface) {
       const gfx::Rect work_area = root_window_controller_->GetWindow()
                                       ->GetDisplayNearestWindow()
                                       .work_area();
       touch_exploration_controller_->SetExcludeBounds(work_area);
       SilenceSpokenFeedback();
       Shell::Get()->accessibility_delegate()->ClearFocusHighlight();
     } else {
       touch_exploration_controller_->SetExcludeBounds(gfx::Rect());
     }
+
+    // Virtual keyboard.
+    keyboard::KeyboardController* keyboard_controller =
+        keyboard::KeyboardController::GetInstance();
+    if (keyboard_controller) {
+      if (!keyboard_controller->HasObserver(this))
+        keyboard_controller->AddObserver(this);
+
+      touch_exploration_controller_->SetLiftActivationBounds(
+          keyboard_controller->current_keyboard_bounds());
+    }
   } else {
     touch_exploration_controller_.reset();
   }
 }
 
 bool AshTouchExplorationManager::VolumeAdjustSoundEnabled() {
   return !base::CommandLine::ForCurrentProcess()->HasSwitch(
       chromeos::switches::kDisableVolumeAdjustSound);
 }
 
 }  // namespace ash