Add tab reparenting

content/browser/android/content_view_core_impl.cc

 // Copyright 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 "content/browser/android/content_view_core_impl.h"
 
 #include <stddef.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
@@ skipping 255 matching lines @@
 
   JNIEnv* env = base::android::AttachCurrentThread();
   ScopedJavaLocalRef<jobject> j_obj = java_ref_.get(env);
   java_ref_.reset();
   if (!j_obj.is_null()) {
     Java_ContentViewCore_onNativeContentViewCoreDestroyed(
         env, j_obj.obj(), reinterpret_cast<intptr_t>(this));
   }
 }
 
+void ContentViewCoreImpl::UpdateWindowAndroid(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj,
+    jlong window_android) {
+  if (window_android) {

[no sievers, 2016/02/25 19:23:16]

What about |window_android_ != null|?

If that is not supposed to happen, can you DCHECK?
Otherwise we might still want to notify OnDetachedFromWindow() first.

[Yusuf, 2016/02/25 19:37:03]

Good point. I would rather DCHECK. Whoever uses this call should be setting it
to null first on the old activity.

+    window_android_ = reinterpret_cast<ui::WindowAndroid*>(window_android);
+    FOR_EACH_OBSERVER(ContentViewCoreImplObserver,
+                      observer_list_,
+                      OnAttachedToWindow());
+  } else {
+    FOR_EACH_OBSERVER(ContentViewCoreImplObserver,
+                      observer_list_,
+                      OnDetachedFromWindow());
+    window_android_ = NULL;
+  }
+}
+
 base::android::ScopedJavaLocalRef<jobject>
 ContentViewCoreImpl::GetWebContentsAndroid(JNIEnv* env,
                                            const JavaParamRef<jobject>& obj) {
   return web_contents_->GetJavaWebContents();
 }
 
 base::android::ScopedJavaLocalRef<jobject>
 ContentViewCoreImpl::GetJavaWindowAndroid(JNIEnv* env,
                                           const JavaParamRef<jobject>& obj) {
   if (!window_android_)
@@ skipping 1235 matching lines @@
     return ScopedJavaLocalRef<jobject>();
 
   return view->GetJavaObject();
 }
 
 bool RegisterContentViewCore(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace content