Add accelerators for ARC++ specific key events

Create boilerplate for changing density in ARC++
applications on user input (CTRL +/CTRL -/CTRL 0)
to simulate the behaviour of the chrome native apps.
BUG=b:142100473
TEST=Manual

Change-Id: I1e58e1b03b2cc07dfeaff22b0e49436936cbc228
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1847032
Commit-Queue: Mikolaj Walczak <walczakm@google.com>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704961}

components/exo/BUILD.gn

@@ -102,6 +102,8 @@ source_set("exo") {
       "//chromeos/constants",
     ]
     sources += [
+      "client_controlled_accelerators.cc",
+      "client_controlled_accelerators.h",
       "client_controlled_shell_surface.cc",
       "client_controlled_shell_surface.h",
       "gaming_seat.cc",

components/exo/client_controlled_accelerators.cc

+// Copyright 2019 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 "components/exo/client_controlled_accelerators.h"
+
+namespace exo {
+
+ClientControlledAcceleratorTarget::ClientControlledAcceleratorTarget(
+    ClientControlledShellSurface* surface)
+    : surface_(surface) {}
+
+ClientControlledAcceleratorTarget::~ClientControlledAcceleratorTarget() =
+    default;
+
+void ClientControlledAcceleratorTarget::RegisterAccelerator(
+    const ui::Accelerator& accelerator,
+    ClientControlledAcceleratorAction action) {
+  accelerators_.insert(std::make_pair(ui::Accelerator{accelerator}, action));
+}
+
+void ClientControlledAcceleratorTarget::RegisterAccelerator(
+    ui::Accelerator&& accelerator,
+    ClientControlledAcceleratorAction action) {
+  accelerators_.insert(std::make_pair(std::move(accelerator), action));
+}
+
+bool ClientControlledAcceleratorTarget::AcceleratorPressed(
+    const ui::Accelerator& accelerator) {
+  auto it = accelerators_.find(accelerator);
+  DCHECK(it != accelerators_.end());
+  ClientControlledAcceleratorAction action = it->second;
+
+  switch (action) {
+    case ClientControlledAcceleratorAction::ZOOM_IN:
+      surface_->ChangeZoomLevel(ZoomChange::IN);
+      break;
+    case ClientControlledAcceleratorAction::ZOOM_OUT:
+      surface_->ChangeZoomLevel(ZoomChange::OUT);
+      break;
+    case ClientControlledAcceleratorAction::ZOOM_RESET:
+      surface_->ChangeZoomLevel(ZoomChange::RESET);
+      break;
+  }
+  return true;
+}
+
+bool ClientControlledAcceleratorTarget::CanHandleAccelerators() const {
+  return true;
+}
+
+}  // namespace exo

components/exo/client_controlled_accelerators.h

+// Copyright 2019 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.
+
+#ifndef COMPONENTS_EXO_CLIENT_CONTROLLED_ACCELERATORS_H_
+#define COMPONENTS_EXO_CLIENT_CONTROLLED_ACCELERATORS_H_
+
+#include "components/exo/client_controlled_shell_surface.h"
+#include "ui/aura/window.h"
+#include "ui/base/accelerators/accelerator.h"
+#include "ui/views/focus/focus_manager.h"
+
+namespace exo {
+
+enum class ClientControlledAcceleratorAction {
+  ZOOM_IN,
+  ZOOM_OUT,
+  ZOOM_RESET,
+};
+
+class ClientControlledShellSurface;
+
+class ClientControlledAcceleratorTarget : public ui::AcceleratorTarget {
+ public:
+  explicit ClientControlledAcceleratorTarget(
+      ClientControlledShellSurface* surface);
+  ~ClientControlledAcceleratorTarget() override;
+
+  void RegisterAccelerator(const ui::Accelerator& accelerator,
+                           ClientControlledAcceleratorAction action);
+  void RegisterAccelerator(ui::Accelerator&& accelerator,
+                           ClientControlledAcceleratorAction action);
+
+  // ui::AcceleratorTarget interface implementation.
+  bool AcceleratorPressed(const ui::Accelerator& accelerator) override;
+  bool CanHandleAccelerators() const override;
+
+ private:
+  ClientControlledShellSurface* surface_;
+  std::map<ui::Accelerator, ClientControlledAcceleratorAction> accelerators_;
+
+  DISALLOW_COPY_AND_ASSIGN(ClientControlledAcceleratorTarget);
+};
+
+}  // namespace exo
+
+#endif  // COMPONENTS_EXO_CLIENT_CONTROLLED_ACCELERATORS_H_

components/exo/client_controlled_shell_surface.cc

@@ -55,6 +55,20 @@ namespace exo {
 
 namespace {
 
+// Client controlled specific accelerators.
+const struct {
+  ui::KeyboardCode keycode;
+  int modifiers;
+  ClientControlledAcceleratorAction action;
+} kAccelerators[] = {
+    {ui::VKEY_OEM_MINUS, ui::EF_CONTROL_DOWN,
+     ClientControlledAcceleratorAction::ZOOM_OUT},
+    {ui::VKEY_OEM_PLUS, ui::EF_CONTROL_DOWN,
+     ClientControlledAcceleratorAction::ZOOM_IN},
+    {ui::VKEY_0, ui::EF_CONTROL_DOWN,
+     ClientControlledAcceleratorAction::ZOOM_RESET},
+};
+
 ClientControlledShellSurface::DelegateFactoryCallback& GetFactoryForTesting() {
   using CallbackType = ClientControlledShellSurface::DelegateFactoryCallback;
   static base::NoDestructor<CallbackType> factory;
@@ -611,6 +625,10 @@ void ClientControlledShellSurface::OnBoundsChangeEvent(
   }
 }
 
+void ClientControlledShellSurface::ChangeZoomLevel(ZoomChange change) {
+  // TODO(walczakm): Send wayland event.
+}
+
 void ClientControlledShellSurface::OnDragStarted(int component) {
   in_drag_ = true;
   if (drag_started_callback_)
@@ -904,6 +922,19 @@ void ClientControlledShellSurface::InitializeWindowState(
   UpdateFrameWidth();
   if (initial_orientation_lock_ != ash::OrientationLockType::kAny)
     SetOrientationLock(initial_orientation_lock_);
+
+  // Register Client controlled accelerators.
+  views::FocusManager* focus_manager = widget_->GetFocusManager();
+  accelerator_target_ =
+      std::make_unique<ClientControlledAcceleratorTarget>(this);
+
+  for (const auto& entry : kAccelerators) {
+    focus_manager->RegisterAccelerator(
+        ui::Accelerator(entry.keycode, entry.modifiers),
+        ui::AcceleratorManager::kNormalPriority, accelerator_target_.get());
+    accelerator_target_->RegisterAccelerator(
+        ui::Accelerator(entry.keycode, entry.modifiers), entry.action);
+  }
 }
 
 float ClientControlledShellSurface::GetScale() const {

components/exo/client_controlled_shell_surface.h

@@ -12,6 +12,7 @@
 #include "ash/wm/client_controlled_state.h"
 #include "base/callback.h"
 #include "base/macros.h"
+#include "components/exo/client_controlled_accelerators.h"
 #include "components/exo/shell_surface_base.h"
 #include "ui/base/hit_test.h"
 #include "ui/compositor/compositor_lock.h"
@@ -30,8 +31,10 @@ enum class WindowPinType;
 
 namespace exo {
 class Surface;
+class ClientControlledAcceleratorTarget;
 
 enum class Orientation { PORTRAIT, LANDSCAPE };
+enum class ZoomChange { IN, OUT, RESET };
 
 // This class implements a ShellSurface whose window state and bounds are
 // controlled by a remote shell client rather than the window manager. The
@@ -154,6 +157,9 @@ class ClientControlledShellSurface : public ShellSurfaceBase,
   // Set resize outset for surface.
   void SetResizeOutset(int outset);
 
+  // Sends the request to change the zoom level to the client.
+  void ChangeZoomLevel(ZoomChange change);
+
   // Sends the window state change event to client.
   void OnWindowStateChangeEvent(ash::WindowStateType old_state,
                                 ash::WindowStateType next_state);
@@ -340,6 +346,9 @@ class ClientControlledShellSurface : public ShellSurfaceBase,
   // True if the window state has changed during the commit.
   bool state_changed_ = false;
 
+  // Client controlled specific accelerator target.
+  std::unique_ptr<ClientControlledAcceleratorTarget> accelerator_target_;
+
   DISALLOW_COPY_AND_ASSIGN(ClientControlledShellSurface);
 };