Implement WebContentsViewChildFrame::TakeFocus.

third_party/WebKit/Source/core/page/FocusController.cpp

Index: third_party/WebKit/Source/core/page/FocusController.cpp
diff --git a/third_party/WebKit/Source/core/page/FocusController.cpp b/third_party/WebKit/Source/core/page/FocusController.cpp
index de9da91658722ce16c2e4d1f9ba55da8cf1a3666..28897fcea19a17f418c11d41059ae6d187670d50 100644
--- a/third_party/WebKit/Source/core/page/FocusController.cpp
+++ b/third_party/WebKit/Source/core/page/FocusController.cpp
@@ -855,7 +855,9 @@ void FocusController::setFocused(bool focused) {
   if (!m_isFocused && focusedOrMainFrame()->isLocalFrame())
     toLocalFrame(focusedOrMainFrame())->eventHandler().stopAutoscroll();
 
-  if (!m_focusedFrame)
+  // Do not set a focused frame when being unfocused. This might reset
+  // m_isFocused to true.
+  if (!m_focusedFrame && m_isFocused)

[dcheng, 2017/01/12 10:19:21]

This seems like a reasonable change to me, but I'm wondering if it's web visible
at all?

[avallee, 2017/01/12 20:00:23]

See the conversation here:
https://codereview.chromium.org/2474323002/diff/60001/third_party/WebKit/Sour...

[dcheng, 2017/01/20 07:02:38]

Would it be better to just pass false for notifyEmbedder here? After reading
this code, I haven't managed to convince myself this is OK. One of the places
that calls this function is WebViewImpl::setFocus(), and there's a fair amount
of work that's performed if there's a focused frame.

How do we end up here without any focused frames at all anyway?

[avallee, 2017/01/20 14:19:11]

Oh, i thought I had previously linked to the spot that clears the frame. If you
look here:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/page/Focu...

In the oopif case, we would hit the previous if block to advance focus out to
the embedder frame:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/page/Focu...

In the webview case, the page thinks it exists by itself, it's a main frame and
has reached the end of the content. In this case it returns focus to the
"Chrome" layer (just a different embedder).

     setFocusedFrame(m_page->mainFrame());
 
   // setFocusedFrame above might reject to update m_focusedFrame, or