Long press menu (shift+f6) to toggle spoken feedback.

ash/magnifier/magnifier_key_scroller.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/magnifier/magnifier_key_scroller.h"
 
-#include <X11/Xlib.h>
-
-#undef RootWindow
-#undef Status
-
+#include "ash/accelerators/key_hold_detector.h"
 #include "ash/ash_switches.h"
 #include "ash/magnifier/magnification_controller.h"
 #include "ash/shell.h"
 #include "base/command_line.h"
-#include "base/message_loop/message_loop.h"
-#include "ui/aura/root_window.h"
-#include "ui/aura/window_tracker.h"
 
 namespace ash {
 namespace {
+bool magnifier_key_scroller_enabled = false;
+}
 
-bool magnifier_key_scroller_enabled = false;
+// static
+bool MagnifierKeyScroller::IsEnabled() {
+  return (magnifier_key_scroller_enabled ||
+          CommandLine::ForCurrentProcess()->HasSwitch(
+              switches::kAshEnableMagnifierKeyScroller)) &&
+      ash::Shell::GetInstance()->magnification_controller()->IsEnabled();
+}
 
-void ScrollScreen(ui::KeyEvent* event) {
+// static
+void MagnifierKeyScroller::SetEnabled(bool enabled) {
+  magnifier_key_scroller_enabled = enabled;
+}
+
+// static
+ui::EventHandler* MagnifierKeyScroller::CreateHandler() {
+  scoped_ptr<KeyHoldDetector::Delegate> delegate(new MagnifierKeyScroller());
+  return new KeyHoldDetector(delegate.Pass());
+}
+
+bool MagnifierKeyScroller::ShouldProcessEvent(const ui::KeyEvent* event) const {
+  return IsEnabled() &&
+      (event->key_code() == ui::VKEY_UP ||
+       event->key_code() == ui::VKEY_DOWN ||
+       event->key_code() == ui::VKEY_LEFT ||
+       event->key_code() == ui::VKEY_RIGHT);
+}
+
+bool MagnifierKeyScroller::IsStartEvent(const ui::KeyEvent* event) const {
+  return event->type() == ui::ET_KEY_PRESSED &&
+      event->flags() & ui::EF_SHIFT_DOWN;
+}
+
+void MagnifierKeyScroller::OnKeyHold(const ui::KeyEvent* event) {
   MagnificationController* controller =
       Shell::GetInstance()->magnification_controller();
   switch (event->key_code()) {
     case ui::VKEY_UP:
       controller->SetScrollDirection(MagnificationController::SCROLL_UP);
       break;
     case ui::VKEY_DOWN:
       controller->SetScrollDirection(MagnificationController::SCROLL_DOWN);
       break;
     case ui::VKEY_LEFT:
       controller->SetScrollDirection(MagnificationController::SCROLL_LEFT);
       break;
     case ui::VKEY_RIGHT:
       controller->SetScrollDirection(MagnificationController::SCROLL_RIGHT);
       break;
     default:
       NOTREACHED() << "Unknown keyboard_code:" << event->key_code();
   }
 }
 
-void DispatchPressedEvent(XEvent native_event,
-                          scoped_ptr<aura::WindowTracker> tracker) {
-  // The target window may be gone.
-  if (tracker->windows().empty())
-    return;
-  aura::Window* target = *(tracker->windows().begin());
-  ui::KeyEvent event(&native_event, false);
-  event.set_flags(event.flags() | ui::EF_IS_SYNTHESIZED);
-  ui::EventDispatchDetails result ALLOW_UNUSED =
-      target->GetDispatcher()->OnEventFromSource(&event);
+void MagnifierKeyScroller::OnKeyUnhold(const ui::KeyEvent* event) {
+  MagnificationController* controller =
+      Shell::GetInstance()->magnification_controller();
+  controller->SetScrollDirection(MagnificationController::SCROLL_NONE);
 }
 
-void PostPressedEvent(ui::KeyEvent* event) {
-  // Modify RELEASED event to PRESSED event.
-  XEvent xkey = *(event->native_event());
-  xkey.xkey.type = KeyPress;
-  xkey.xkey.state |= ShiftMask;
-  scoped_ptr<aura::WindowTracker> tracker(new aura::WindowTracker);
-  tracker->Add(static_cast<aura::Window*>(event->target()));
-
-  base::MessageLoopForUI::current()->PostTask(
-      FROM_HERE,
-      base::Bind(&DispatchPressedEvent, xkey, base::Passed(&tracker)));
-}
-
-}  // namespace
-
-// static
-bool MagnifierKeyScroller::IsEnabled() {
-  return (magnifier_key_scroller_enabled ||
-          CommandLine::ForCurrentProcess()->HasSwitch(
-              switches::kAshEnableMagnifierKeyScroller)) &&
-      ash::Shell::GetInstance()->magnification_controller()->IsEnabled();
-}
-
-// static
-void MagnifierKeyScroller::SetEnabled(bool enabled) {
-  magnifier_key_scroller_enabled = enabled;
-}
-
-MagnifierKeyScroller::MagnifierKeyScroller()
-    : state_(INITIAL) {}
+MagnifierKeyScroller::MagnifierKeyScroller() {}
 
 MagnifierKeyScroller::~MagnifierKeyScroller() {}
 
-void MagnifierKeyScroller::OnKeyEvent(
-    ui::KeyEvent* event) {
-  if (!IsEnabled())
-    return;
-
-  if (event->key_code() != ui::VKEY_UP &&
-      event->key_code() != ui::VKEY_DOWN &&
-      event->key_code() != ui::VKEY_LEFT &&
-      event->key_code() != ui::VKEY_RIGHT) {
-    return;
-  }
-
-  if (event->type() == ui::ET_KEY_PRESSED &&
-      event->flags() & ui::EF_SHIFT_DOWN) {
-    switch (state_) {
-      case INITIAL:
-        // Pass through posted event.
-        if (event->flags() & ui::EF_IS_SYNTHESIZED) {
-          event->set_flags(event->flags() & ~ui::EF_IS_SYNTHESIZED);
-          return;
-        }
-        state_ = PRESSED;
-        // Don't process ET_KEY_PRESSED event yet. The ET_KEY_PRESSED
-        // event will be generated upon ET_KEY_RELEASEED event below.
-        event->StopPropagation();
-        break;
-      case PRESSED:
-        state_ = HOLD;
-        // pass through
-      case HOLD:
-        ScrollScreen(event);
-        event->StopPropagation();
-        break;
-      }
-  } else if (event->type() == ui::ET_KEY_RELEASED) {
-    switch (state_) {
-      case INITIAL:
-        break;
-      case PRESSED: {
-        PostPressedEvent(event);
-        event->StopPropagation();
-        break;
-      }
-      case HOLD: {
-        MagnificationController* controller =
-            Shell::GetInstance()->magnification_controller();
-        controller->SetScrollDirection(MagnificationController::SCROLL_NONE);
-        event->StopPropagation();
-        break;
-      }
-    }
-    state_ = INITIAL;
-  }
-}
-
 }  // namespace ash