Implement touch exploration touch typing

ash/ash_touch_exploration_manager_chromeos.cc

Index: ash/ash_touch_exploration_manager_chromeos.cc
diff --git a/ash/ash_touch_exploration_manager_chromeos.cc b/ash/ash_touch_exploration_manager_chromeos.cc
index 6120ffbf4de19d4c49fe0ea4118585cf05818dad..565b42993f8c07db222296d0b084f5ab8df61b11 100644
--- a/ash/ash_touch_exploration_manager_chromeos.cc
+++ b/ash/ash_touch_exploration_manager_chromeos.cc
@@ -18,6 +18,7 @@
 #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 {
@@ -36,6 +37,10 @@ AshTouchExplorationManager::AshTouchExplorationManager(
 }
 
 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)
@@ -142,6 +147,15 @@ void AshTouchExplorationManager::SetTouchAccessibilityAnchorPoint(
   }
 }
 
+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 =
@@ -176,6 +190,17 @@ void AshTouchExplorationManager::UpdateTouchExplorationState() {
     } 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();
   }