Makes delay commitText/setComposition can deal with empty text/composition.

chrome/browser/ui/input_method/input_method_engine.cc

 // Copyright 2016 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/ui/input_method/input_method_engine.h"
 
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/url_constants.h"
@@ skipping 132 matching lines @@
                                  false /* thick */, SK_ColorTRANSPARENT));
   }
 
   ui::IMEInputContextHandlerInterface* input_context =
       ui::IMEBridge::Get()->GetInputContextHandler();
   // If the IME extension is handling key event, hold the composition text
   // until the key event is handled.
   if (input_context && !handling_key_event_) {
     input_context->UpdateCompositionText(composition_, cursor_pos, is_visible);
     composition_.Clear();
+  } else {
+    composition_changed_ = true;
   }
 }
 
 void InputMethodEngine::CommitTextToInputContext(int context_id,
                                                  const std::string& text) {
   // Append the text to the buffer, as it allows committing text multiple times
   // when processing a key event.
   text_ += text;
 
   ui::IMEInputContextHandlerInterface* input_context =
       ui::IMEBridge::Get()->GetInputContextHandler();
   // If the IME extension is handling key event, hold the text until the key
   // event is handled.
   if (input_context && !handling_key_event_) {
     input_context->CommitText(text_);
     text_ = "";
+  } else {
+    commit_text_changed_ = true;
   }
 }
 
 void InputMethodEngine::OnWindowDestroyed(ui::ImeWindow* ime_window) {
   if (ime_window == follow_cursor_window_) {
     follow_cursor_window_ = nullptr;
   } else {
     auto it = std::find(
         normal_windows_.begin(), normal_windows_.end(), ime_window);
     if (it != normal_windows_.end())
@@ skipping 91 matching lines @@
   }
 
   // Whitelists Backspace key and arrow keys.
   std::vector<ui::KeyboardCode> whitelist_keycodes{
       ui::VKEY_BACK, ui::VKEY_LEFT, ui::VKEY_RIGHT, ui::VKEY_UP, ui::VKEY_DOWN};
   return std::find(whitelist_keycodes.begin(), whitelist_keycodes.end(),
                    ui_event->key_code()) != whitelist_keycodes.end();
 }
 
 }  // namespace input_method