[KeyboardLock] Adding a SystemKeyboardLock feature

This feature controls whether the low-level keyboard hook is enabled
when keyboard lock is requested.  I wanted to separate browser and
system level keyboard lock functionality as I get closer to launching
the blink api for keyboard lock.  This will allow us to release
browser-level keyboard lock w/o the system hooks if needed and will
also give us the ability to target a finch kill switch for the
system-level functionality if needed.

BUG=680809

Change-Id: I2d522046c90fd8776bfb1d9c53978f2c41e1c7cc
Reviewed-on: https://chromium-review.googlesource.com/1046154Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Joe Downing <joedow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558367}

chrome/browser/about_flags.cc

@@ -2255,6 +2255,9 @@ const FeatureEntry kFeatureEntries[] = {
     {"keyboard-lock-api", flag_descriptions::kKeyboardLockApiName,
      flag_descriptions::kKeyboardLockApiDescription, kOsDesktop,
      FEATURE_VALUE_TYPE(features::kKeyboardLockAPI)},
+    {"system-keyboard-lock", flag_descriptions::kSystemKeyboardLockName,
+     flag_descriptions::kSystemKeyboardLockDescription, kOsDesktop,
+     FEATURE_VALUE_TYPE(features::kSystemKeyboardLock)},
     {"experimental-keyboard-lock-ui",
      flag_descriptions::kExperimentalKeyboardLockUiName,
      flag_descriptions::kExperimentalKeyboardLockUiDescription, kOsDesktop,

chrome/browser/flag_descriptions.cc

@@ -1593,6 +1593,12 @@ const char kSyncSandboxName[] = "Use Chrome Sync sandbox";
 const char kSyncSandboxDescription[] =
     "Connects to the testing server for Chrome Sync.";
 
+const char kSystemKeyboardLockName[] = "Experimental system keyboard lock";
+const char kSystemKeyboardLockDescription[] =
+    "Enables websites to use the keyboard.lock() API to intercept system "
+    "keyboard shortcuts and have the events routed directly to the website "
+    "when in fullscreen mode.";
+
 const char kTabAudioMutingName[] = "Tab audio muting UI control";
 const char kTabAudioMutingDescription[] =
     "When enabled, the audio indicators in the tab strip double as tab audio "

chrome/browser/flag_descriptions.h

@@ -964,6 +964,9 @@ extern const char kStopLoadingInBackgroundDescription[];
 extern const char kStopNonTimersInBackgroundName[];
 extern const char kStopNonTimersInBackgroundDescription[];
 
+extern const char kSystemKeyboardLockName[];
+extern const char kSystemKeyboardLockDescription[];
+
 extern const char kTLS13VariantName[];
 extern const char kTLS13VariantDescription[];
 extern const char kTLS13VariantDisabled[];

tools/metrics/histograms/enums.xml

@@ -26489,6 +26489,7 @@ from previous Chrome versions.
   <int value="-1946522787" label="VrCustomTabBrowsing:disabled"/>
   <int value="-1945524394" label="EnableBackgroundBlur:disabled"/>
   <int value="-1943507605" label="enable-new-video-renderer"/>
+  <int value="-1943313820" label="SystemKeyboardLock:disabled"/>
   <int value="-1941852572" label="floating-virtual-keyboard"/>
   <int value="-1940806558" label="enable-syncfs-directory-operation"/>
   <int value="-1940377152" label="MacRTL:enabled"/>
@@ -27775,6 +27776,7 @@ from previous Chrome versions.
   <int value="986796748" label="AccountConsistency:enabled"/>
   <int value="988981463" label="ImageCaptureAPI:enabled"/>
   <int value="989062160" label="ModuleScriptsImportMetaUrl:enabled"/>
+  <int value="996701528" label="SystemKeyboardLock:enabled"/>
   <int value="996797157" label="V8ContextSnapshot:enabled"/>
   <int value="1000587036" label="OfflinePagesDescriptiveFailStatus:disabled"/>
   <int value="1000706989" label="AutomaticTabDiscarding:disabled"/>

ui/aura/BUILD.gn

@@ -70,6 +70,7 @@ jumbo_component("aura") {
     "mus/window_tree_host_mus_delegate.h",
     "mus/window_tree_host_mus_init_params.h",
     "scoped_keyboard_hook.h",
+    "scoped_simple_keyboard_hook.h",
     "scoped_window_targeter.h",
     "window.h",
     "window_delegate.h",
@@ -134,6 +135,7 @@ jumbo_component("aura") {
     "mus/window_tree_host_mus.cc",
     "mus/window_tree_host_mus_init_params.cc",
     "scoped_keyboard_hook.cc",
+    "scoped_simple_keyboard_hook.cc",
     "scoped_window_targeter.cc",
     "window.cc",
     "window_event_dispatcher.cc",

ui/aura/scoped_simple_keyboard_hook.cc

+// Copyright 2018 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 "ui/aura/scoped_simple_keyboard_hook.h"
+
+#include <utility>
+
+#include "base/stl_util.h"
+#include "ui/events/keycodes/dom/dom_code.h"
+
+namespace aura {
+
+ScopedSimpleKeyboardHook::ScopedSimpleKeyboardHook(
+    base::Optional<base::flat_set<ui::DomCode>> dom_codes)
+    : dom_codes_(std::move(dom_codes)) {}
+
+ScopedSimpleKeyboardHook::~ScopedSimpleKeyboardHook() = default;
+
+bool ScopedSimpleKeyboardHook::IsKeyLocked(ui::DomCode dom_code) {
+  if (dom_code == ui::DomCode::NONE)
+    return false;
+
+  return !dom_codes_ || base::ContainsKey(dom_codes_.value(), dom_code);
+}
+
+}  // namespace aura

ui/aura/scoped_simple_keyboard_hook.h

+// Copyright 2018 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 UI_AURA_SCOPED_SIMPLE_KEYBOARD_HOOK_H_
+#define UI_AURA_SCOPED_SIMPLE_KEYBOARD_HOOK_H_
+
+#include "base/containers/flat_set.h"
+#include "base/macros.h"
+#include "base/optional.h"
+#include "ui/aura/scoped_keyboard_hook.h"
+
+namespace ui {
+enum class DomCode;
+}
+
+namespace aura {
+
+// This subclass of ScopedKeyboardHook will not set up a system-level keyboard
+// hook or call into any WindowTreeHost methods for lock state or cleanup.
+// It allows for disabling system-level keyboard lock functionality while
+// continuing to support browser-level keyboard lock.
+// TODO(joedow): Remove this class after 'system-keyboard-lock' is removed.
+class ScopedSimpleKeyboardHook : public ScopedKeyboardHook {
+ public:
+  explicit ScopedSimpleKeyboardHook(
+      base::Optional<base::flat_set<ui::DomCode>> dom_codes);
+  ~ScopedSimpleKeyboardHook() override;
+
+  // ScopedKeyboardHook override.
+  bool IsKeyLocked(ui::DomCode dom_code) override;
+
+ private:
+  base::Optional<base::flat_set<ui::DomCode>> dom_codes_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedSimpleKeyboardHook);
+};
+
+}  // namespace aura
+
+#endif  // UI_AURA_SCOPED_SIMPLE_KEYBOARD_HOOK_H_

ui/aura/window_tree_host.cc

@@ -5,6 +5,7 @@
 #include "ui/aura/window_tree_host.h"
 
 #include "base/command_line.h"
+#include "base/feature_list.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
@@ -13,6 +14,7 @@
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/scoped_keyboard_hook.h"
+#include "ui/aura/scoped_simple_keyboard_hook.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_port.h"
@@ -21,6 +23,7 @@
 #include "ui/base/ime/input_method.h"
 #include "ui/base/ime/input_method_factory.h"
 #include "ui/base/layout.h"
+#include "ui/base/ui_base_features.h"
 #include "ui/base/view_prop.h"
 #include "ui/compositor/compositor_switches.h"
 #include "ui/compositor/dip_util.h"
@@ -274,8 +277,12 @@ void WindowTreeHost::Hide() {
 }
 
 std::unique_ptr<ScopedKeyboardHook> WindowTreeHost::CaptureSystemKeyEvents(
-    base::Optional<base::flat_set<ui::DomCode>> codes) {
-  if (CaptureSystemKeyEventsImpl(std::move(codes)))
+    base::Optional<base::flat_set<ui::DomCode>> dom_codes) {
+  // TODO(joedow): Remove the simple hook class/logic once this flag is removed.
+  if (!base::FeatureList::IsEnabled(features::kSystemKeyboardLock))
+    return std::make_unique<ScopedSimpleKeyboardHook>(std::move(dom_codes));
+
+  if (CaptureSystemKeyEventsImpl(std::move(dom_codes)))
     return std::make_unique<ScopedKeyboardHook>(weak_factory_.GetWeakPtr());
   return nullptr;
 }

ui/base/ui_base_features.cc

@@ -42,6 +42,10 @@ const base::Feature kSecondaryUiMd = {"SecondaryUiMd",
 #endif
 };
 
+// Allows system keyboard event capture when |features::kKeyboardLockApi| is on.
+const base::Feature kSystemKeyboardLock{"SystemKeyboardLock",
+                                        base::FEATURE_DISABLED_BY_DEFAULT};
+
 const base::Feature kTouchableAppContextMenu = {
     "EnableTouchableAppContextMenu", base::FEATURE_DISABLED_BY_DEFAULT};
 

ui/base/ui_base_features.h

@@ -19,6 +19,7 @@ UI_BASE_EXPORT extern const base::Feature
     kEnableFullscreenHandwritingVirtualKeyboard;
 UI_BASE_EXPORT extern const base::Feature kEnableStylusVirtualKeyboard;
 UI_BASE_EXPORT extern const base::Feature kSecondaryUiMd;
+UI_BASE_EXPORT extern const base::Feature kSystemKeyboardLock;
 UI_BASE_EXPORT extern const base::Feature kTouchableAppContextMenu;
 UI_BASE_EXPORT extern const base::Feature kUiCompositorScrollWithLayers;
 

ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc

@@ -573,6 +573,7 @@ bool DesktopWindowTreeHostWin::CaptureSystemKeyEventsImpl(
       std::move(dom_codes), GetAcceleratedWidget(),
       base::BindRepeating(&DesktopWindowTreeHostWin::HandleKeyEvent,
                           base::Unretained(this)));
+
   return keyboard_hook_ != nullptr;
 }
 

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

@@ -1311,6 +1311,7 @@ bool DesktopWindowTreeHostX11::CaptureSystemKeyEventsImpl(
       std::move(dom_codes), GetAcceleratedWidget(),
       base::BindRepeating(&DesktopWindowTreeHostX11::DispatchKeyEvent,
                           base::Unretained(this)));
+
   return keyboard_hook_ != nullptr;
 }