Implement chrome.input.ime.setComposition/commitText API.

ui/base/ime/input_method_win.cc

Index: ui/base/ime/input_method_win.cc
diff --git a/ui/base/ime/input_method_win.cc b/ui/base/ime/input_method_win.cc
index 6ac7e6f1219d2dc86704a87e8ce44893cfe2b7d8..176f7111bd5e137cfeb92072782a2e93ed6abee1 100644
--- a/ui/base/ime/input_method_win.cc
+++ b/ui/base/ime/input_method_win.cc
@@ -178,6 +178,9 @@ void InputMethodWin::DispatchKeyEvent(ui::KeyEvent* event) {
           switches::kDisableMergeKeyCharEvents) &&
       char_msgs.size() <= 1 && GetEngine() &&
       GetEngine()->IsInterestedInKeyEvent()) {
+    // Make true that we don't handle IME API calling of setComposition and
+    // commitText while the extension is processing key event.
+    handling_key_event_ = true;
     ui::IMEEngineHandlerInterface::KeyEventDoneCallback callback = base::Bind(
         &InputMethodWin::ProcessKeyEventDone, weak_ptr_factory_.GetWeakPtr(),
         base::Owned(new ui::KeyEvent(*event)),
@@ -191,6 +194,7 @@ void InputMethodWin::DispatchKeyEvent(ui::KeyEvent* event) {
 void InputMethodWin::ProcessKeyEventDone(ui::KeyEvent* event,
                                          const std::vector<MSG>* char_msgs,
                                          bool is_handled) {
+  handling_key_event_ = false;
   DCHECK(event);
   if (is_handled)
     return;