Proposed alternative for supporting ChromeVox keyboard commands.

chrome/browser/chromeos/accessibility/spoken_feedback_event_rewriter.cc

Index: chrome/browser/chromeos/accessibility/spoken_feedback_event_rewriter.cc
diff --git a/chrome/browser/chromeos/accessibility/spoken_feedback_event_rewriter.cc b/chrome/browser/chromeos/accessibility/spoken_feedback_event_rewriter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..56fa8dcd269375dc9967af706f6233bde962f4da
--- /dev/null
+++ b/chrome/browser/chromeos/accessibility/spoken_feedback_event_rewriter.cc
@@ -0,0 +1,76 @@
+// Copyright 2015 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 "chrome/browser/chromeos/accessibility/spoken_feedback_event_rewriter.h"
+
+#include <string>
+
+#include "base/values.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/common/extensions/api/commands/commands_handler.h"
+#include "chrome/common/extensions/extension_constants.h"
+#include "extensions/browser/event_router.h"
+#include "extensions/browser/extension_registry.h"
+#include "ui/events/event.h"
+
+SpokenFeedbackEventRewriter::SpokenFeedbackEventRewriter() {
+}
+
+SpokenFeedbackEventRewriter::~SpokenFeedbackEventRewriter() {
+}
+
+ui::EventRewriteStatus SpokenFeedbackEventRewriter::RewriteEvent(
+    const ui::Event& event,
+    scoped_ptr<ui::Event>* new_event) {
+  if (!chromeos::AccessibilityManager::Get()->IsSpokenFeedbackEnabled() ||
+      event.type() != ui::ET_KEY_PRESSED ||

[dmazzoni, 2015/06/16 16:30:56]

I think you need to handle ET_KEY_RELEASED too. You may need to handle sequences
of events that start out as non-cvox keys but later the search key gets added so
the sequence all becomes a cvox event. We should have tests for those sequences.

Check out touch_exploration_controller_unittest.cc for some examples of writing
event rewriter unit tests.

[David Tseng, 2015/06/17 22:22:10]

If you discard a press event, I think the release gets discarded.

 You may need to handle sequences
Example? Do you mean Search+Shift+n, b (where b is unmodified)? This does appear
to break with this change.
I was thinking about just constructing a SpokenFeedbackEventTest directly and
calling |RewriteEvent|. Would hat suffice and asserting the continue/discard
return?

+      !g_browser_process->profile_manager())
+    return ui::EVENT_REWRITE_CONTINUE;
+
+  content::BrowserContext* context =
+      g_browser_process->profile_manager()->GetLastUsedProfile();
+
+  const extensions::Extension* extension =
+      extensions::ExtensionRegistry::Get(context)->enabled_extensions().GetByID(
+          extension_misc::kChromeVoxExtensionId);
+  if (!extension)
+    return ui::EVENT_REWRITE_CONTINUE;
+
+  const extensions::CommandMap* commands =
+      extensions::CommandsInfo::GetNamedCommands(extension);
+  if (!commands)
+    return ui::EVENT_REWRITE_CONTINUE;
+
+  const ui::KeyEvent key_event = static_cast<const ui::KeyEvent&>(event);
+  std::string command_name;
+  for (extensions::CommandMap::const_iterator iter = commands->begin();
+       iter != commands->end(); ++iter) {
+    if (iter->second.accelerator().key_code() == key_event.key_code() &&
+        iter->second.accelerator().modifiers() == key_event.flags())
+      command_name = iter->second.command_name();
+  }
+
+  if (command_name.empty())
+    return ui::EVENT_REWRITE_CONTINUE;
+
+  scoped_ptr<base::ListValue> args(new base::ListValue());
+  args->Append(new base::StringValue(command_name));
+
+  scoped_ptr<extensions::Event> extension_event(
+      new extensions::Event("commands.onCommand", args.Pass()));
+  extension_event->restrict_to_browser_context = context;
+
+  extensions::EventRouter::Get(context)->DispatchEventToExtension(
+      extension_misc::kChromeVoxExtensionId, extension_event.Pass());
+
+  return ui::EVENT_REWRITE_DISCARD;
+}
+
+ui::EventRewriteStatus SpokenFeedbackEventRewriter::NextDispatchEvent(
+    const ui::Event& last_event,
+    scoped_ptr<ui::Event>* new_event) {
+  return ui::EVENT_REWRITE_CONTINUE;
+}