Merge 228079 "Revert 221394 "Remove IBus specific hack from Inpu..."

> Revert 221394 "Remove IBus specific hack from InputMethodIBus."
> 
> > Remove IBus specific hack from InputMethodIBus.
> > 
> > BUG=None
> > TEST=None, just working fine.
> > 
> > Review URL: https://chromiumcodereview.appspot.com/22909048
> 
> TBR=nona@chromium.org
> 
> Review URL: https://codereview.chromium.org/26262003

TBR=nona@chromium.org

Review URL: https://codereview.chromium.org/27286002

git-svn-id: svn://svn.chromium.org/chrome/branches/1650/src@228593 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 25 insertions, 5 deletions

diff --git a/ui/base/ime/input_method_ibus.cc b/ui/base/ime/input_method_ibus.cc
index 5db106e..8ff645a 100644
--- a/ui/base/ime/input_method_ibus.cc
+++ b/ui/base/ime/input_method_ibus.cc
@@ -80,6 +80,7 @@ InputMethodIBus::InputMethodIBus(
     : context_focused_(false),
       composing_text_(false),
       composition_changed_(false),
+      suppress_next_result_(false),
       current_keyevent_id_(0),
       previous_textinput_type_(TEXT_INPUT_TYPE_NONE),
       weak_ptr_factory_(this) {
@@ -202,6 +203,10 @@ bool InputMethodIBus::DispatchKeyEvent(const base::NativeEvent& native_event) {
                  ibus_state));
 
   ++current_keyevent_id_;
+
+  // We don't want to suppress the result generated by this key event, but it
+  // may cause problem. See comment in ResetContext() method.
+  suppress_next_result_ = false;
   return true;
 }
 
@@ -347,6 +352,16 @@ void InputMethodIBus::ResetContext() {
 
   DCHECK(system_toplevel_window_focused());
 
+  // Because ibus runs in asynchronous mode, the input method may still send us
+  // results after sending out the reset request, so we use a flag to discard
+  // all results generated by previous key events. But because ibus does not
+  // have a mechanism to identify each key event and corresponding results, this
+  // approach will not work for some corner cases. For example if the user types
+  // very fast, then the next key event may come in before the |context_| is
+  // really reset. Then we actually cannot know whether or not the next
+  // result should be discard.
+  suppress_next_result_ = true;
+
   composition_.Clear();
   result_text_.clear();
   composing_text_ = false;
@@ -562,7 +577,7 @@ void InputMethodIBus::AbandonAllPendingKeyEvents() {
 }
 
 void InputMethodIBus::CommitText(const chromeos::IBusText& text) {
-  if (text.text().empty())
+  if (suppress_next_result_ || text.text().empty())
     return;
 
   // We need to receive input method result even if the text input type is
@@ -612,7 +627,7 @@ void InputMethodIBus::ForwardKeyEvent(uint32 keyval,
 }
 
 void InputMethodIBus::ShowPreeditText() {
-  if (IsTextInputTypeNone())
+  if (suppress_next_result_ || IsTextInputTypeNone())
     return;
 
   composing_text_ = true;
@@ -621,6 +636,9 @@ void InputMethodIBus::ShowPreeditText() {
 void InputMethodIBus::UpdatePreeditText(const chromeos::IBusText& text,
                                         uint32 cursor_pos,
                                         bool visible) {
+  if (suppress_next_result_ || IsTextInputTypeNone())
+    return;
+
   if (!CanComposeInline()) {
     chromeos::IBusPanelCandidateWindowHandlerInterface* candidate_window =
         chromeos::IBusBridge::Get()->GetCandidateWindowHandler();
@@ -628,9 +646,6 @@ void InputMethodIBus::UpdatePreeditText(const chromeos::IBusText& text,
       candidate_window->UpdatePreeditText(text.text(), cursor_pos, visible);
   }
 
-  if (IsTextInputTypeNone())
-    return;
-
   // |visible| argument is very confusing. For example, what's the correct
   // behavior when:
   // 1. OnUpdatePreeditText() is called with a text and visible == false, then
@@ -693,6 +708,7 @@ bool InputMethodIBus::ExecuteCharacterComposer(uint32 ibus_keyval,
       ibus_keycode,
       EventFlagsFromXState(ibus_state));
 
+  suppress_next_result_ = false;
   chromeos::IBusText preedit;
   preedit.set_text(
       UTF16ToUTF8(character_composer_.preedit_string()));
diff --git a/ui/base/ime/input_method_ibus.h b/ui/base/ime/input_method_ibus.h
index 4393225..3be172f 100644
--- a/ui/base/ime/input_method_ibus.h
+++ b/ui/base/ime/input_method_ibus.h
@@ -166,6 +166,10 @@ class UI_EXPORT InputMethodIBus
   // Indicates if the composition text is changed or deleted.
   bool composition_changed_;
 
+  // If it's true then all input method result received before the next key
+  // event will be discarded.
+  bool suppress_next_result_;
+
   // The latest id of key event.
   uint32 current_keyevent_id_;