Fix the incorrect native ImeAdapter attach and detach.

content/browser/android/content_view_core_impl.cc

Index: content/browser/android/content_view_core_impl.cc
diff --git a/content/browser/android/content_view_core_impl.cc b/content/browser/android/content_view_core_impl.cc
index ccdc2e0271bb7dd8da93ee8210f0d3351ad4268b..322650c3d4de77fd9c9ded187e8b708809e6b83e 100644
--- a/content/browser/android/content_view_core_impl.cc
+++ b/content/browser/android/content_view_core_impl.cc
@@ -219,6 +219,9 @@ void ContentViewCoreImpl::InitWebContents() {
   notification_registrar_.Add(
       this, NOTIFICATION_WEB_CONTENTS_CONNECTED,
       Source<WebContents>(web_contents_));
+  notification_registrar_.Add(
+      this, NOTIFICATION_WEB_CONTENTS_SWAPPED,
+      Source<WebContents>(web_contents_));
 
   static_cast<WebContentsViewAndroid*>(web_contents_->GetView())->
       SetContentViewCore(this);
@@ -278,6 +281,13 @@ void ContentViewCoreImpl::Observe(int type,
       }
       break;
     }
+    case NOTIFICATION_WEB_CONTENTS_SWAPPED: {
+      JNIEnv* env = AttachCurrentThread();
+      ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
+      if (!obj.is_null()) {
+        Java_ContentViewCore_onWebContentsSwapped(env, obj.obj());
+      }
+    }
   }
 }