+sanfin, tsunghung; I don't know what container view switching is, but I do know that we're actively working on removing video hole codepath from Cast on Android TV.

Container View switching would be if you give the ContentViewCore a different ContentView (CVC.setContainerView()) at any time.

what about the one from PopupTouchHandleDrawable? that's gonna be refactored away in some other way?

VIDEO_HOLE hole punching is disabled in m52 webview, so if no one yells when that goes to stable, it can be removed entirely from webview

Thanks for pointing out that call site which I missed. I don't understand how any of that does the right thing by listening to View position changes. What matters here is the content position and when you change the structure of the View then this triggers a layout and the handles need to be repositioned as dictated by the renderer. The only use case I can think of otherwise is if the View moves but the content doesn't change (same size). For going in and out of fullscreen in particular though (i.e. container view change) this seems like it would certainly involve a relayout.

Does it maybe have to do with how WebView does scrolling?
It seems to temporarily hide handles when the position changes.
And then it also uses the View position as an offset to put the handles in the right place. Also I guess this code is only used by WebView nowadays.
But if this is just for propagating scroll offsets maybe this can be done in a different way that doesn't require the PopupTouchHandleDrawable to know about the container view changing.

I think maybe we can move PopupTouchHandleDrawable to webview so that the container view update event can be passed directly between them without cvc and inject it to content. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5356a1399fdc2e940db8553788ed2c540e5abe68

commit 5356a1399fdc2e940db8553788ed2c540e5abe68
Author: jinsukkim <jinsukkim@chromium.org>
Date: Wed Aug 31 02:26:27 2016

android_webview: Let AwContents manage TouchHandleDrawable

WebView's text selection handles(TouchHandleDrawables) should be
notified when their container view gets swapped out to be
repositioned accordingly. This is now being done through
|ContainerViewObserver| in |ContentViewCore| which is slated for
removal as a part of content layer refactoring.

This CL makes use of a new interface method in
|SynchronousCompositorClent| to let AwContents manage the handles
directly, and notify them of the event of the container view switching.

BUG= 624977 

Review-Url: https://codereview.chromium.org/2263043002
Cr-Commit-Position: refs/heads/master@{#415542}

[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/BUILD.gn
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/android_webview.gyp
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/browser/browser_view_renderer.cc
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/browser/browser_view_renderer.h
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/browser/browser_view_renderer_client.h
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/browser/test/rendering_test.cc
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/browser/test/rendering_test.h
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/java/src/org/chromium/android_webview/AwContents.java
[rename] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/java/src/org/chromium/android_webview/PopupTouchHandleDrawable.java
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/native/BUILD.gn
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/native/DEPS
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/native/aw_contents.cc
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/native/aw_contents.h
[rename] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/native/popup_touch_handle_drawable.cc
[rename] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/android_webview/native/popup_touch_handle_drawable.h
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/content/browser/android/synchronous_compositor_host.h
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/content/browser/renderer_host/render_widget_host_view_android.cc
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/content/content_browser.gypi
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/content/content_jni.gypi
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/content/public/android/BUILD.gn
[modify] https://crrev.com/5356a1399fdc2e940db8553788ed2c540e5abe68/content/public/browser/android/synchronous_compositor_client.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/03c7e50720e3a9e79cc2b443269b8327bbe52475

commit 03c7e50720e3a9e79cc2b443269b8327bbe52475
Author: jinsukkim <jinsukkim@chromium.org>
Date: Mon Sep 19 00:20:09 2016

Remove ContainerViewObserver

ContainerViewObserver is used by ExternalVideoSurfaceContainer
only, which in turn used by Chromecast/WebView.

Since Chromecast never updates container view in its lifecycle,
it can go without using ContainerViewObserver. And WebView
disabled support for video hole since M52.

With that, ContainerViewObserver is not used any more. This CL
deletes the class.

BUG= 624977 

Review-Url: https://codereview.chromium.org/2293743002
Cr-Commit-Position: refs/heads/master@{#419403}

[modify] https://crrev.com/03c7e50720e3a9e79cc2b443269b8327bbe52475/components/external_video_surface/android/java/src/org/chromium/components/external_video_surface/ExternalVideoSurfaceContainer.java
[modify] https://crrev.com/03c7e50720e3a9e79cc2b443269b8327bbe52475/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e03ab3adcb3134c665843469613c9a7faba46b5b

commit e03ab3adcb3134c665843469613c9a7faba46b5b
Author: jinsukkim <jinsukkim@chromium.org>
Date: Thu Sep 22 00:06:03 2016

Remove ContainerViewObserver class

Removes the class left unused after refactoring

BUG= 624977 

Review-Url: https://codereview.chromium.org/2360863002
Cr-Commit-Position: refs/heads/master@{#420208}

[modify] https://crrev.com/e03ab3adcb3134c665843469613c9a7faba46b5b/content/public/android/BUILD.gn
[delete] https://crrev.com/72e9876bdadd8cb4df5e813d03b5ca8d966d214f/content/public/android/java/src/org/chromium/content/browser/ContainerViewObserver.java