CrOS - Make it possible to Alt+Tab while dragging a tab

ash/wm/window_cycle_event_filter_aura.cc

Index: ash/wm/window_cycle_event_filter_aura.cc
diff --git a/ash/wm/window_cycle_event_filter_aura.cc b/ash/wm/window_cycle_event_filter_aura.cc
index e9879b524f7005f9be2261aba4139640fdcb0daa..a8dadb9a8c8c068a8dc41e96875b5f7c9f792eb9 100644
--- a/ash/wm/window_cycle_event_filter_aura.cc
+++ b/ash/wm/window_cycle_event_filter_aura.cc
@@ -14,10 +14,16 @@ namespace ash {
 
 WindowCycleEventFilterAura::WindowCycleEventFilterAura() {
   Shell::GetInstance()->AddPreTargetHandler(this);
+  // Handling release of "Alt" must come before other pretarget handlers
+  // (specifically, the partial screenshot handler). See crbug.com/651939
+  // We can't do all key event handling that early though because it prevents
+  // other accelerators (like triggering a partial screenshot) from working.
+  Shell::GetInstance()->PrependPreTargetHandler(&alt_release_handler_);
 }
 
 WindowCycleEventFilterAura::~WindowCycleEventFilterAura() {
   Shell::GetInstance()->RemovePreTargetHandler(this);
+  Shell::GetInstance()->RemovePreTargetHandler(&alt_release_handler_);
 }
 
 void WindowCycleEventFilterAura::OnKeyEvent(ui::KeyEvent* event) {
@@ -28,12 +34,7 @@ void WindowCycleEventFilterAura::OnKeyEvent(ui::KeyEvent* event) {
       event->type() != ui::ET_KEY_PRESSED) {
     event->StopPropagation();
   }
-  // Views uses VKEY_MENU for both left and right Alt keys.
-  if (event->key_code() == ui::VKEY_MENU &&
-      event->type() == ui::ET_KEY_RELEASED) {
-    WmShell::Get()->window_cycle_controller()->CompleteCycling();
-    // Warning: |this| will be deleted from here on.
-  } else if (event->key_code() == ui::VKEY_TAB) {
+  if (event->key_code() == ui::VKEY_TAB) {
     if (event->type() == ui::ET_KEY_RELEASED) {
       repeat_timer_.Stop();
     } else if (event->type() == ui::ET_KEY_PRESSED && event->is_repeat() &&
@@ -51,4 +52,28 @@ void WindowCycleEventFilterAura::OnKeyEvent(ui::KeyEvent* event) {
   }
 }
 
+void WindowCycleEventFilterAura::OnMouseEvent(ui::MouseEvent* event) {
+  // Prevent mouse clicks from doing anything while the Alt+Tab UI is active
+  // <crbug.com/641171> but don't interfere with drag and drop operations
+  // <crbug.com/660945>.
+  if (event->type() != ui::ET_MOUSE_DRAGGED &&
+      event->type() != ui::ET_MOUSE_RELEASED) {
+    event->StopPropagation();
+  }
+}
+
+WindowCycleEventFilterAura::AltReleaseHandler::AltReleaseHandler() {}
+
+WindowCycleEventFilterAura::AltReleaseHandler::~AltReleaseHandler() {}
+
+void WindowCycleEventFilterAura::AltReleaseHandler::OnKeyEvent(
+    ui::KeyEvent* event) {
+  // Views uses VKEY_MENU for both left and right Alt keys.
+  if (event->key_code() == ui::VKEY_MENU &&
+      event->type() == ui::ET_KEY_RELEASED) {
+    WmShell::Get()->window_cycle_controller()->CompleteCycling();
+    // Warning: |this| will be deleted from here on.
+  }
+}
+
 }  // namespace ash