Set the current input context handler when the toplevel window is activated instead of when the inp…

ui/base/ime/input_method_base.cc

Index: ui/base/ime/input_method_base.cc
diff --git a/ui/base/ime/input_method_base.cc b/ui/base/ime/input_method_base.cc
index 5d53a1943dcf1ff8bb907d7d585e33dfa451b63b..e4af2e847995cdde30ed6120aaecff569a8052bb 100644
--- a/ui/base/ime/input_method_base.cc
+++ b/ui/base/ime/input_method_base.cc
@@ -17,7 +17,7 @@
 namespace ui {
 
 InputMethodBase::InputMethodBase()
-    : delegate_(NULL), text_input_client_(NULL) {}
+    : delegate_(nullptr), text_input_client_(nullptr) {}
 
 InputMethodBase::~InputMethodBase() {
   FOR_EACH_OBSERVER(InputMethodObserver,
@@ -32,20 +32,25 @@ void InputMethodBase::SetDelegate(internal::InputMethodDelegate* delegate) {
   delegate_ = delegate;
 }
 
-void InputMethodBase::OnFocus() {}
+void InputMethodBase::OnFocus() {
+  if (ui::IMEBridge::Get())
+    ui::IMEBridge::Get()->SetInputContextHandler(this);
+}
 
-void InputMethodBase::OnBlur() {}
+void InputMethodBase::OnBlur() {
+  if (ui::IMEBridge::Get() &&
+      ui::IMEBridge::Get()->GetInputContextHandler() == this)
+    ui::IMEBridge::Get()->SetInputContextHandler(nullptr);
+}
 
 void InputMethodBase::SetFocusedTextInputClient(TextInputClient* client) {
   SetFocusedTextInputClientInternal(client);
-  if (ui::IMEBridge::Get())
-    ui::IMEBridge::Get()->SetInputContextHandler(this);
 }
 
 void InputMethodBase::DetachTextInputClient(TextInputClient* client) {
   if (text_input_client_ != client)
     return;
-  SetFocusedTextInputClientInternal(NULL);
+  SetFocusedTextInputClientInternal(nullptr);
 }
 
 TextInputClient* InputMethodBase::GetTextInputClient() const {
@@ -131,7 +136,7 @@ void InputMethodBase::SetFocusedTextInputClientInternal(
   if (old == client)
     return;
   OnWillChangeFocusedClient(old, client);
-  text_input_client_ = client;  // NULL allowed.
+  text_input_client_ = client;  // nullptr allowed.
   OnDidChangeFocusedClient(old, client);
   NotifyTextInputStateChanged(text_input_client_);
 }