Combine the WM_CHAR with WM_KEY* for key event flow.

ui/base/ime/input_method_win.cc

 // Copyright (c) 2012 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 "ui/base/ime/input_method_win.h"
 
 #include "base/auto_reset.h"
 #include "base/basictypes.h"
 #include "base/profiler/scoped_tracker.h"
 #include "ui/base/ime/text_input_client.h"
@@ skipping 14 matching lines @@
 
 }  // namespace
 
 InputMethodWin::InputMethodWin(internal::InputMethodDelegate* delegate,
                                HWND toplevel_window_handle)
     : toplevel_window_handle_(toplevel_window_handle),
       pending_requested_direction_(base::i18n::UNKNOWN_DIRECTION),
       accept_carriage_return_(false),
       enabled_(false),
       is_candidate_popup_open_(false),
-      composing_window_handle_(NULL),
-      suppress_next_char_(false) {
+      composing_window_handle_(NULL) {
   SetDelegate(delegate);
 }
 
 void InputMethodWin::OnFocus() {
   InputMethodBase::OnFocus();
   if (GetTextInputClient())
     UpdateIMEState();
 }
 
 void InputMethodWin::OnBlur() {
@@ skipping 50 matching lines @@
     *result = original_result;
   return !!handled;
 }
 
 void InputMethodWin::DispatchKeyEvent(ui::KeyEvent* event) {
   if (!event->HasNativeEvent()) {
     DispatchFabricatedKeyEvent(event);
     return;
   }
 
+  std::vector<MSG> char_msgs;
   const base::NativeEvent& native_key_event = event->native_event();
+  // Peek & remove the following messages in the message queue.
+  //  - WM_CHAR (0x0102)
+  //  - WM_DEADCHAR (0x0103)
+  //  - WM_SYSCHAR (0x0106)
+  //  - WM_SYSDEADCHAR (0x0107)
+  // And only process WM_CHAR & WM_SYSCHAR message in browser.
+  // This is to combine the WM_KEY* and WM_CHAR messages in the event
+  // processing flow which is necessary to let Chrome IME extension to process
+  // the key event and perform corresponding IME actions.
+  // Chrome IME extension may wants to consume certain key events based on
+  // the character information of WM_CHAR messages. Holding WM_KEY* messages
+  // until WM_CHAR is processed by the IME extension is not feasible because
+  // there is no way to know wether there will or not be a WM_CHAR following
+  // the WM_KEY*.
+  // Chrome never handles dead chars so it is safe to remove/ignore
+  // WM_*DEADCHAR messages.
+  MSG msg;
+  while (::PeekMessage(&msg, native_key_event.hwnd, WM_CHAR, WM_DEADCHAR,
+                       PM_REMOVE)) {
+    if (msg.message == WM_CHAR)
+      char_msgs.push_back(msg);
+  }
+  while (::PeekMessage(&msg, native_key_event.hwnd, WM_SYSCHAR, WM_SYSDEADCHAR,
+                       PM_REMOVE)) {
+    if (msg.message == WM_SYSCHAR)
+      char_msgs.push_back(msg);
+  }
+
+  BOOL handled = FALSE;
   if (native_key_event.message == WM_CHAR) {
-    BOOL handled;
     OnChar(native_key_event.hwnd, native_key_event.message,
            native_key_event.wParam, native_key_event.lParam, &handled);
     if (handled)
       event->StopPropagation();
     return;
   }
   // Handles ctrl-shift key to change text direction and layout alignment.
   if (ui::IMM32Manager::IsRTLKeyboardLayoutInstalled() &&
       !IsTextInputTypeNone()) {
     // TODO: shouldn't need to generate a KeyEvent here.
@@ skipping 10 matching lines @@
     } else if (key.type() == ui::ET_KEY_RELEASED &&
                (code == ui::VKEY_SHIFT || code == ui::VKEY_CONTROL) &&
                pending_requested_direction_ != base::i18n::UNKNOWN_DIRECTION) {
       GetTextInputClient()->ChangeTextDirectionAndLayoutAlignment(
           pending_requested_direction_);
       pending_requested_direction_ = base::i18n::UNKNOWN_DIRECTION;
     }
   }
 
   ui::EventDispatchDetails details = DispatchKeyEventPostIME(event);
-  if (!details.dispatcher_destroyed)
-    suppress_next_char_ = event->stopped_propagation();
+  if (details.dispatcher_destroyed || details.target_destroyed ||
+      event->stopped_propagation()) {
+    return;
+  }
+
+  for (size_t i = 0; i < char_msgs.size(); ++i) {
+    msg = char_msgs[i];
+    OnChar(msg.hwnd, msg.message, msg.wParam, msg.lParam, &handled);
+  }
 }
 
 void InputMethodWin::OnTextInputTypeChanged(const TextInputClient* client) {
   if (!IsTextInputClientFocused(client) || !IsWindowFocused(client))
     return;
   imm32_manager_.CancelIME(toplevel_window_handle_);
   UpdateIMEState();
 }
 
 void InputMethodWin::OnCaretBoundsChanged(const TextInputClient* client) {
@@ skipping 65 matching lines @@
                                UINT message,
                                WPARAM wparam,
                                LPARAM lparam,
                                BOOL* handled) {
   // TODO(vadimt): Remove ScopedTracker below once crbug.com/440919 is fixed.
   tracked_objects::ScopedTracker tracking_profile(
       FROM_HERE_WITH_EXPLICIT_FUNCTION("440919 InputMethodWin::OnChar"));
 
   *handled = TRUE;
 
-  if (suppress_next_char_) {
-    suppress_next_char_ = false;
-    return 0;
-  }
-
   // We need to send character events to the focused text input client event if
   // its text input type is ui::TEXT_INPUT_TYPE_NONE.
   if (GetTextInputClient()) {
     const base::char16 kCarriageReturn = L'\r';
     const base::char16 ch = static_cast<base::char16>(wparam);
     // A mask to determine the previous key state from |lparam|. The value is 1
     // if the key is down before the message is sent, or it is 0 if the key is
     // up.
     const uint32 kPrevKeyDownBit = 0x40000000;
     if (ch == kCarriageReturn && !(lparam & kPrevKeyDownBit))
@@ skipping 338 matching lines @@
   // window. So we can safely assume that |attached_window_handle| is ready for
   // receiving keyboard input as long as it is an active window. This works well
   // even when the |attached_window_handle| becomes active but has not received
   // WM_FOCUS yet.
   return toplevel_window_handle_ &&
       GetActiveWindow() == toplevel_window_handle_;
 }
 
 void InputMethodWin::DispatchFabricatedKeyEvent(ui::KeyEvent* event) {
   if (event->is_char()) {
-    if (suppress_next_char_) {
-      suppress_next_char_ = false;
-      return;
-    }
     if (GetTextInputClient()) {
       GetTextInputClient()->InsertChar(
           static_cast<base::char16>(event->key_code()),
           ui::GetModifiersFromKeyState());
       return;
     }
   }
   ignore_result(DispatchKeyEventPostIME(event));
 }
 
@@ skipping 27 matching lines @@
       enabled_ = true;
       break;
   }
 
   imm32_manager_.SetTextInputMode(window_handle, text_input_mode);
   tsf_inputscope::SetInputScopeForTsfUnawareWindow(
       window_handle, text_input_type, text_input_mode);
 }
 
 }  // namespace ui