exo: Do not send the key event already consumed by the system IME.

When a key event is filtered by IME, its key_code() is masked by VKEY_PROCESSKEY
but code() is kept as-is. Such a filtered key event should not be sent to the
client in unmasked form. Otherwise the event is double-handled.

BUG=597197

Review URL: https://codereview.chromium.org/1828643002

Cr-Commit-Position: refs/heads/master@{#382839}

1 files changed, 8 insertions, 2 deletions

diff --git a/components/exo/keyboard.cc b/components/exo/keyboard.cc
index 89437e0..dc50522 100644
--- a/components/exo/keyboard.cc
+++ b/components/exo/keyboard.cc
@@ -52,12 +52,18 @@ void Keyboard::OnKeyEvent(ui::KeyEvent* event) {
       delegate_->OnKeyboardModifiers(modifier_flags_);
   }
 
+  // When IME ate a key event, it re-sends the event after masking |key_code|
+  // by VKEY_PROCESSKEY. Although such events can be used to track the key
+  // states, they should not be sent as unmasked key events. Otherwise they are
+  // handled in two places (IME and client) and cause undesired behavior.
+  bool consumed_by_ime = (event->key_code() == ui::VKEY_PROCESSKEY);
+
   switch (event->type()) {
     case ui::ET_KEY_PRESSED: {
       auto it =
           std::find(pressed_keys_.begin(), pressed_keys_.end(), event->code());
       if (it == pressed_keys_.end()) {
-        if (focus_)
+        if (focus_ && !consumed_by_ime)
           delegate_->OnKeyboardKey(event->time_stamp(), event->code(), true);
 
         pressed_keys_.push_back(event->code());
@@ -67,7 +73,7 @@ void Keyboard::OnKeyEvent(ui::KeyEvent* event) {
       auto it =
           std::find(pressed_keys_.begin(), pressed_keys_.end(), event->code());
       if (it != pressed_keys_.end()) {
-        if (focus_)
+        if (focus_ && !consumed_by_ime)
           delegate_->OnKeyboardKey(event->time_stamp(), event->code(), false);
 
         pressed_keys_.erase(it);