BtBrl: add necessary bindings to initialize bluetooth braille

- Adds an extension api, chrome.brailleDisplayPrivate.updateBluetoothBrailleDisplayAddress, which will [re]start brltty with the given device.
- adds a pref to track the braille display desired by a given user
- adds logic to start and stop brltty on launch given a bluetooth braille display

TODO:
- the UI which will do the initial connection/pairing, and unpairing/forgetting of a device

Bug: 882261
Test: manually call all relevant api functions.
Change-Id: Ief0189a3f76ea6518bd8b644d3df816435feb019
- call chrome.brailleDisplayPrivate.updateBluetoothBrailleDisplayAddress
- observe brltty is launched with the given address
- unload and reload chromevox and observe brltty is appropriately loaded/unloaded

Depends on:
https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/1308895

Change-Id: Ief0189a3f76ea6518bd8b644d3df816435feb019
Reviewed-on: https://chromium-review.googlesource.com/c/1308986
Commit-Queue: David Tseng <dtseng@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605185}

chrome/browser/chromeos/accessibility/accessibility_manager.cc

@@ -28,6 +28,7 @@
 #include "base/strings/string_piece.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 #include "base/task/post_task.h"
 #include "base/values.h"
 #include "chrome/browser/accessibility/accessibility_extension_api.h"
@@ -58,6 +59,7 @@
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/power_manager_client.h"
+#include "chromeos/dbus/upstart_client.h"
 #include "components/language/core/browser/pref_names.h"
 #include "components/prefs/pref_member.h"
 #include "components/prefs/pref_service.h"
@@ -110,6 +112,13 @@ const char kUserSpokenFeedbackEnabled[] = "UserSpokenFeedbackEnabled";
 // A key for the startup sound enabled boolean state for a known user.
 const char kUserStartupSoundEnabled[] = "UserStartupSoundEnabled";
 
+// A key for the bluetooth braille display for a user.
+const char kUserBluetoothBrailleDisplayAddress[] =
+    "UserBluetoothBrailleDisplayAddress";
+
+// The name of the Brltty upstart job.
+constexpr char kBrlttyUpstartJobName[] = "brltty";
+
 static chromeos::AccessibilityManager* g_accessibility_manager = nullptr;
 
 static BrailleController* g_braille_controller_for_test = nullptr;
@@ -133,6 +142,24 @@ void EnableSwitchAccessAfterChromeVoxMetric(bool val) {
   UMA_HISTOGRAM_BOOLEAN("Accessibility.CrosSwitchAccessAfterChromeVox", val);
 }
 
+// Restarts (stops, then starts brltty). If |address| is empty, only stops.
+// In Upstart, sending an explicit restart command is a no-op if the job isn't
+// already started. Without knowledge regarding brltty's current job status,
+// stop followed by start ensures we both stop a started job, and also start
+// brltty.
+void RestartBrltty(const std::string& address) {
+  chromeos::UpstartClient* client =
+      chromeos::DBusThreadManager::Get()->GetUpstartClient();
+  client->StopJob(kBrlttyUpstartJobName, EmptyVoidDBusMethodCallback());
+
+  std::vector<std::string> args;
+  if (address.empty())
+    return;
+
+  args.push_back(base::StringPrintf("ADDRESS=%s", address.c_str()));
+  client->StartJob(kBrlttyUpstartJobName, args, EmptyVoidDBusMethodCallback());
+}
+
 }  // namespace
 
 class AccessibilityPanelWidgetObserver : public views::WidgetObserver {
@@ -1260,6 +1287,11 @@ void AccessibilityManager::PostLoadChromeVox() {
     return;
 
   // Do any setup work needed immediately after ChromeVox actually loads.
+  // Maybe start brltty, if we have a bluetooth device stored for connection.
+  const std::string& address = GetBluetoothBrailleDisplayAddress();
+  if (!address.empty())
+    RestartBrltty(address);
+
   PlayEarcon(SOUND_SPOKEN_FEEDBACK_ENABLED, PlaySoundOption::ALWAYS);
 
   extensions::EventRouter* event_router =
@@ -1291,6 +1323,10 @@ void AccessibilityManager::PostLoadChromeVox() {
 
 void AccessibilityManager::PostUnloadChromeVox() {
   // Do any teardown work needed immediately after ChromeVox actually unloads.
+  // Stop brltty.
+  chromeos::DBusThreadManager::Get()->GetUpstartClient()->StopJob(
+      kBrlttyUpstartJobName, EmptyVoidDBusMethodCallback());
+
   PlayEarcon(SOUND_SPOKEN_FEEDBACK_DISABLED, PlaySoundOption::ALWAYS);
 
   // Clear the accessibility focus ring.
@@ -1464,6 +1500,35 @@ void AccessibilityManager::SetStartupSoundEnabled(bool value) const {
       kUserStartupSoundEnabled, value);
 }
 
+const std::string AccessibilityManager::GetBluetoothBrailleDisplayAddress()
+    const {
+  user_manager::UserManager* user_manager = user_manager::UserManager::Get();
+  const user_manager::UserList& user_list = user_manager->GetUsers();
+  if (user_list.empty())
+    return std::string();
+
+  // |user_list| is sorted by last log in date. Take the most recent user to log
+  // in.
+  std::string val;
+  return user_manager::known_user::GetStringPref(
+             user_list[0]->GetAccountId(), kUserBluetoothBrailleDisplayAddress,
+             &val)
+             ? val
+             : std::string();
+}
+
+void AccessibilityManager::UpdateBluetoothBrailleDisplayAddress(
+    const std::string& address) {
+  CHECK(spoken_feedback_enabled_);
+  if (!profile_)
+    return;
+
+  user_manager::known_user::SetStringPref(
+      multi_user_util::GetAccountIdFromProfile(profile_),
+      kUserBluetoothBrailleDisplayAddress, address);
+  RestartBrltty(address);
+}
+
 void AccessibilityManager::SetProfileForTest(Profile* profile) {
   SetProfile(profile);
 }

chrome/browser/chromeos/accessibility/accessibility_manager.h

@@ -313,6 +313,12 @@ class AccessibilityManager
   // Sets the startup sound user preference.
   void SetStartupSoundEnabled(bool value) const;
 
+  // Gets the bluetooth braille display device address for the current user.
+  const std::string GetBluetoothBrailleDisplayAddress() const;
+
+  // Sets the bluetooth braille display device address for the current user.
+  void UpdateBluetoothBrailleDisplayAddress(const std::string& address);
+
   // Test helpers:
   void SetProfileForTest(Profile* profile);
   static void SetBrailleControllerForTest(

chrome/browser/extensions/api/braille_display_private/braille_display_private_api.cc

@@ -13,6 +13,7 @@
 #include "chrome/browser/profiles/profile_manager.h"
 
 #if defined(OS_CHROMEOS)
+#include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
 #include "chrome/browser/chromeos/login/lock/screen_locker.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #endif
@@ -184,5 +185,20 @@ void BrailleDisplayPrivateWriteDotsFunction::Work() {
 bool BrailleDisplayPrivateWriteDotsFunction::Respond() {
   return true;
 }
+
+ExtensionFunction::ResponseAction
+BrailleDisplayPrivateUpdateBluetoothBrailleDisplayAddressFunction::Run() {
+#if !defined(OS_CHROMEOS)
+  NOTREACHED();
+  return RespondNow(Error("Unsupported on this platform."));
+#else
+  std::string address;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetString(0, &address));
+  chromeos::AccessibilityManager::Get()->UpdateBluetoothBrailleDisplayAddress(
+      address);
+  return RespondNow(NoArguments());
+#endif
+}
+
 }  // namespace api
 }  // namespace extensions

chrome/browser/extensions/api/braille_display_private/braille_display_private_api.h

@@ -106,6 +106,16 @@ class BrailleDisplayPrivateWriteDotsFunction : public AsyncApiFunction {
   std::unique_ptr<braille_display_private::WriteDots::Params> params_;
 };
 
+class BrailleDisplayPrivateUpdateBluetoothBrailleDisplayAddressFunction
+    : public UIThreadExtensionFunction {
+  ~BrailleDisplayPrivateUpdateBluetoothBrailleDisplayAddressFunction()
+      override {}
+  ResponseAction Run() override;
+  DECLARE_EXTENSION_FUNCTION(
+      "brailleDisplayPrivate.updateBluetoothBrailleDisplayAddress",
+      BRAILLEDISPLAYPRIVATE_UPDATEBLUETOOTHBRAILLEDISPLAYADDRESS)
+};
+
 }  // namespace api
 }  // namespace extensions
 

chrome/common/extensions/api/braille_display_private.idl

@@ -74,6 +74,10 @@ namespace brailleDisplayPrivate {
     // parameters give the original 2D dimensions of the buffer. To access
     // an element cells[r][c], simply access cells[r * columns + c].
     static void writeDots(ArrayBuffer cells, long columns, long rows);
+
+    // Updates the single user-preferred braille device with the given bluetooth
+    // device address and starts or restarts the Brltty daemon.
+    static void updateBluetoothBrailleDisplayAddress(DOMString address);
   };
 
   interface Events {

chromeos/dbus/fake_upstart_client.cc

@@ -24,6 +24,12 @@ void FakeUpstartClient::StartJob(const std::string& job,
       FROM_HERE, base::BindOnce(std::move(callback), true));
 }
 
+void FakeUpstartClient::StopJob(const std::string& job,
+                                VoidDBusMethodCallback callback) {
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::BindOnce(std::move(callback), true));
+}
+
 void FakeUpstartClient::StartAuthPolicyService() {
   static_cast<FakeAuthPolicyClient*>(
       DBusThreadManager::Get()->GetAuthPolicyClient())

chromeos/dbus/fake_upstart_client.h

@@ -19,10 +19,12 @@ class CHROMEOS_EXPORT FakeUpstartClient : public UpstartClient {
   // DBusClient overrides.
   void Init(dbus::Bus* bus) override;
 
+  // UpstartClient overrides:
   void StartJob(const std::string& job,
                 const std::vector<std::string>& upstart_env,
                 VoidDBusMethodCallback callback) override;
-  // UpstartClient overrides.
+  void StopJob(const std::string& job,
+               VoidDBusMethodCallback callback) override;
   void StartAuthPolicyService() override;
   void RestartAuthPolicyService() override;
   void StartMediaAnalytics(const std::vector<std::string>& upstart_env,

chromeos/dbus/upstart_client.cc

@@ -30,13 +30,18 @@ class UpstartClientImpl : public UpstartClient {
 
   ~UpstartClientImpl() override = default;
 
+  // UpstartClient overrides:
   void StartJob(const std::string& job,
                 const std::vector<std::string>& upstart_env,
                 VoidDBusMethodCallback callback) override {
     CallJobMethod(job, kStartMethod, upstart_env, std::move(callback));
   }
 
-  // UpstartClient override.
+  void StopJob(const std::string& job,
+               VoidDBusMethodCallback callback) override {
+    CallJobMethod(job, kStopMethod, {}, std::move(callback));
+  }
+
   void StartAuthPolicyService() override {
     StartJob(kAuthPolicyJob, {}, EmptyVoidDBusMethodCallback());
   }
@@ -56,12 +61,11 @@ class UpstartClientImpl : public UpstartClient {
   }
 
   void StopMediaAnalytics() override {
-    CallJobMethod(kMediaAnalyticsJob, kStopMethod, {},
-                  EmptyVoidDBusMethodCallback());
+    StopJob(kMediaAnalyticsJob, EmptyVoidDBusMethodCallback());
   }
 
   void StopMediaAnalytics(VoidDBusMethodCallback callback) override {
-    CallJobMethod(kMediaAnalyticsJob, kStopMethod, {}, std::move(callback));
+    StopJob(kMediaAnalyticsJob, std::move(callback));
   }
  protected:
   void Init(dbus::Bus* bus) override {

chromeos/dbus/upstart_client.h

@@ -31,10 +31,17 @@ class CHROMEOS_EXPORT UpstartClient : public DBusClient {
   // |job|: Name of Upstart job.
   // |upstart_env|: List of upstart environment variables to be passed to the
   // upstart service.
+  // |callback|: Called with a response.
   virtual void StartJob(const std::string& job,
                         const std::vector<std::string>& upstart_env,
                         VoidDBusMethodCallback callback) = 0;
 
+  // Stops an Upstart job.
+  // |job|: Name of Upstart job.
+  // |callback|: Called with a response.
+  virtual void StopJob(const std::string& job,
+                       VoidDBusMethodCallback callback) = 0;
+
   // Starts authpolicyd.
   virtual void StartAuthPolicyService() = 0;
 

extensions/browser/extension_function_histogram_value.h

@@ -1351,6 +1351,7 @@ enum HistogramValue {
   FILEMANAGERPRIVATEINTERNAL_GETLINUXPACKAGEINFO = 1288,
   TABS_GOFORWARD = 1289,
   TABS_GOBACK = 1290,
+  BRAILLEDISPLAYPRIVATE_UPDATEBLUETOOTHBRAILLEDISPLAYADDRESS = 1291,
   // Last entry: Add new entries above, then run:
   // python tools/metrics/histograms/update_extension_histograms.py
   ENUM_BOUNDARY

tools/metrics/histograms/enums.xml

@@ -15742,7 +15742,7 @@ Called by update_net_error_codes.py.-->
   <int value="338" label="CAST_CHANNEL_ON_MESSAGE"/>
   <int value="339" label="CAST_CHANNEL_ON_ERROR"/>
   <int value="340" label="SCREENLOCK_PRIVATE_ON_CHANGED"/>
-  <int value="341" label="SCREENLOCK_PRIVATE_ON_AUTH_ATTEMPTED"/>
+  <int value="341" label="DELETED_SCREENLOCK_PRIVATE_ON_AUTH_ATTEMPTED"/>
   <int value="342" label="TYPES_CHROME_SETTING_ON_CHANGE"/>
   <int value="343"
       label="DELETED_TYPES_PRIVATE_CHROME_DIRECT_SETTING_ON_CHANGE"/>
@@ -17182,6 +17182,8 @@ Called by update_net_error_codes.py.-->
   <int value="1288" label="FILEMANAGERPRIVATEINTERNAL_GETLINUXPACKAGEINFO"/>
   <int value="1289" label="TABS_GOFORWARD"/>
   <int value="1290" label="TABS_GOBACK"/>
+  <int value="1291"
+      label="BRAILLEDISPLAYPRIVATE_UPDATEBLUETOOTHBRAILLEDISPLAYADDRESS"/>
 </enum>
 
 <enum name="ExtensionIconState">