Use an EventRewriter to ensure Select-to-Speak always gets key events.

The EventRewriter is able to get events before they are even passed to
the system menus, which allows Select-to-Speak to have a chance to
process key events before the menus can stop key event propagation.

This change basically refactors select_to_speak_event_handler* to
select_to_speak_event_rewriter*. It neither adds nor removes tests.

Bug: 791809,793950
Change-Id: Ied4c937e0ff1bcb2c56121f048d185290f4a168e
Reviewed-on: https://chromium-review.googlesource.com/823280
Commit-Queue: Katie D <katie@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524748}

chrome/browser/chromeos/BUILD.gn

@@ -114,10 +114,10 @@ source_set("chromeos") {
     "//components/session_manager/core",
     "//components/signin/core/browser",
     "//components/ssl_config",
+    "//components/startup_metric_utils/browser:lib",
     "//components/storage_monitor",
     "//components/sync_preferences",
     "//components/sync_wifi",
-    "//components/startup_metric_utils/browser:lib",
     "//components/toolbar",
     "//components/tracing:startup_tracing",
     "//components/ukm/content",
@@ -241,8 +241,8 @@ source_set("chromeos") {
     "accessibility/event_handler_common.h",
     "accessibility/magnification_manager.cc",
     "accessibility/magnification_manager.h",
-    "accessibility/select_to_speak_event_handler.cc",
-    "accessibility/select_to_speak_event_handler.h",
+    "accessibility/select_to_speak_event_rewriter.cc",
+    "accessibility/select_to_speak_event_rewriter.h",
     "accessibility/spoken_feedback_event_rewriter.cc",
     "accessibility/spoken_feedback_event_rewriter.h",
     "accessibility/switch_access_event_handler.cc",
@@ -1714,7 +1714,7 @@ source_set("unit_tests") {
     "../policy/default_geolocation_policy_handler_unittest.cc",
     "../ui/browser_finder_chromeos_unittest.cc",
     "accessibility/magnification_manager_unittest.cc",
-    "accessibility/select_to_speak_event_handler_unittest.cc",
+    "accessibility/select_to_speak_event_rewriter_unittest.cc",
     "accessibility/spoken_feedback_event_rewriter_unittest.cc",
     "arc/accessibility/arc_accessibility_helper_bridge_unittest.cc",
     "arc/arc_play_store_enabled_preference_handler_unittest.cc",

chrome/browser/chromeos/accessibility/accessibility_manager.cc

@@ -42,7 +42,6 @@
 #include "chrome/browser/chromeos/accessibility/accessibility_extension_loader.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_highlight_manager.h"
 #include "chrome/browser/chromeos/accessibility/magnification_manager.h"
-#include "chrome/browser/chromeos/accessibility/select_to_speak_event_handler.h"
 #include "chrome/browser/chromeos/accessibility/switch_access_event_handler.h"
 #include "chrome/browser/chromeos/app_mode/kiosk_app_manager.h"
 #include "chrome/browser/chromeos/ash_config.h"
@@ -969,14 +968,10 @@ void AccessibilityManager::UpdateSelectToSpeakFromPref() {
     return;
   select_to_speak_enabled_ = enabled;
 
-  if (enabled) {
+  if (enabled)
     select_to_speak_loader_->Load(profile_, base::Closure() /* done_cb */);
-    select_to_speak_event_handler_.reset(
-        new chromeos::SelectToSpeakEventHandler());
-  } else {
+  else
     select_to_speak_loader_->Unload();
-    select_to_speak_event_handler_.reset(nullptr);
-  }
 }
 
 void AccessibilityManager::SetSwitchAccessEnabled(bool enabled) {

chrome/browser/chromeos/accessibility/accessibility_manager.h

@@ -42,7 +42,6 @@ namespace chromeos {
 class AccessibilityExtensionLoader;
 class AccessibilityHighlightManager;
 class ScopedKeyboardStateSetter;
-class SelectToSpeakEventHandler;
 class SwitchAccessEventHandler;
 
 enum AccessibilityNotificationType {
@@ -439,9 +438,6 @@ class AccessibilityManager
 
   std::unique_ptr<AccessibilityExtensionLoader> select_to_speak_loader_;
 
-  std::unique_ptr<chromeos::SelectToSpeakEventHandler>
-      select_to_speak_event_handler_;
-
   std::unique_ptr<AccessibilityExtensionLoader> switch_access_loader_;
 
   std::unique_ptr<chromeos::SwitchAccessEventHandler>