[FYI] All-in-one OnCandidateWindow{Show,Update,Hide}

ui/base/ime/win/tsf_bridge.cc

Index: ui/base/ime/win/tsf_bridge.cc
diff --git a/ui/base/ime/win/tsf_bridge.cc b/ui/base/ime/win/tsf_bridge.cc
index bf2820323ef297a99dade58ca8ae4dad0a478ab1..f5117391ff719b58878b64447bb37c0f25ab8de5 100644
--- a/ui/base/ime/win/tsf_bridge.cc
+++ b/ui/base/ime/win/tsf_bridge.cc
@@ -6,9 +6,11 @@
 
 #include <map>
 
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/threading/thread_local_storage.h"
 #include "base/win/scoped_comptr.h"
@@ -28,7 +30,8 @@ base::ThreadLocalStorage::StaticSlot tls_tsf_bridge = TLS_INITIALIZER;
 // TsfBridgeDelegate -----------------------------------------------------------
 
 // A TLS implementation of TSFBridge.
-class TSFBridgeDelegate : public TSFBridge {
+class TSFBridgeDelegate : public TSFBridge,
+                          public base::SupportsWeakPtr<TSFBridgeDelegate> {
  public:
   TSFBridgeDelegate();
   virtual ~TSFBridgeDelegate();
@@ -46,6 +49,13 @@ class TSFBridgeDelegate : public TSFBridge {
   virtual base::win::ScopedComPtr<ITfThreadMgr> GetThreadManager() OVERRIDE;
   virtual TextInputClient* GetFocusedTextInputClient() const OVERRIDE;
 
+  // See also *Callback functions below. To avoid reentrancy issue that
+  // TextInputClient manipulates IME state during even handling, these methods
+  // defer sending actual signals to renderer.
+  virtual void OnCandidateWindowShown() OVERRIDE;
+  virtual void OnCandidateWindowUpdated() OVERRIDE;
+  virtual void OnCandidateWindowHidden() OVERRIDE;
+
  private:
   // Returns true if |tsf_document_map_| is successfully initialized. This
   // method should be called from and only from Initialize().
@@ -90,6 +100,12 @@ class TSFBridgeDelegate : public TSFBridge {
   void UpdateAssociateFocus();
   void ClearAssociateFocus();
 
+  // Deferred callbacks for signalling TextInputClient about candidate window
+  // appearance changes.
+  void CandidateWindowShownCallback();
+  void CandidateWindowUpdatedCallback();
+  void CandidateWindowHiddenCallback();
+
   // A triple of document manager, text store and binding cookie between
   // a context owned by the document manager and the text store. This is a
   // minimum working set of an editable document in TSF.
@@ -484,6 +500,45 @@ TSFBridgeDelegate::TSFDocument* TSFBridgeDelegate::GetAssociatedDocument() {
   return &it->second;
 }
 
+void TSFBridgeDelegate::OnCandidateWindowShown() {
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&TSFBridgeDelegate::CandidateWindowShownCallback,
+                 AsWeakPtr()));
+}
+
+void TSFBridgeDelegate::OnCandidateWindowUpdated() {
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&TSFBridgeDelegate::CandidateWindowUpdatedCallback,
+                 AsWeakPtr()));
+}
+
+void TSFBridgeDelegate::OnCandidateWindowHidden() {
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&TSFBridgeDelegate::CandidateWindowHiddenCallback,
+                 AsWeakPtr()));
+}
+
+void TSFBridgeDelegate::CandidateWindowShownCallback() {
+  TextInputClient* client = GetFocusedTextInputClient();
+  if (client)
+      client->OnCandidateWindowShown();
+}
+
+void TSFBridgeDelegate::CandidateWindowUpdatedCallback() {
+  TextInputClient* client = GetFocusedTextInputClient();
+  if (client)
+      client->OnCandidateWindowUpdated();
+}
+
+void TSFBridgeDelegate::CandidateWindowHiddenCallback() {
+  TextInputClient* client = GetFocusedTextInputClient();
+  if (client)
+      client->OnCandidateWindowHidden();
+}
+
 }  // namespace