When BackForwardCache is enabled and the user navigates the main frame
back/forward a new RFH may be created for an existing main frame GlobalId value
and CefFrameHostImpl (e.g. an object that was previously Detach()ed after main
frame navigation called SetMainFrame, but for which RenderFrameDeleted was not
subsequently called due to insertion in the BackForwardCache). In this case we
can re-attach the new RFH to the existing main frame CefFrameHostImpl in
RenderFrameHostStateChanged and resume processing of messages.
Swapping back/forward to an existing (already loaded) renderer does not trigger
new notifications for draggable regions (e.g. RenderFrameObserver::
DraggableRegionsChanged is not called by default). We therefore explicitly
request an update of draggable regions by sending the DidStopLoading message to
the renderer.
A new |reattached| parameter is added to CefFrameHandler::OnFrameAttached to
support identification of BackForwardCache usage by the client.
To test with unit tests:
Run `ceftests --gtest_filter=DraggableRegionsTest.DraggableRegionsCrossOrigin
--enable-features=BackForwardCache`
To test manually:
1. Run `cefclient --enable-features=BackForwardCache --use-views
--url=http://tests/draggable`, note that draggable regions work.
2. Load https://www.google.com via the address bar, note that draggable regions
are removed.
3. Go back to http://tests/draggable, note that draggable regions work.
4. Go forward to https://www.google.com, note that draggable regions are
removed.
This change moves the SendProcessMessage method from CefBrowser to CefFrame and
adds CefBrowser parameters to OnProcessMessageReceived and
OnDraggableRegionsChanged.
The internal implementation has changed as follows:
- Frame IDs are now a 64-bit combination of the 32-bit render_process_id and
render_routing_id values that uniquely identify a RenderFrameHost (RFH).
- CefFrameHostImpl objects are now managed by CefBrowserInfo with life span tied
to RFH expectations. Specifically, a CefFrameHostImpl object representing a
sub-frame will be created when a RenderFrame is created in the renderer
process and detached when the associated RenderFrame is deleted or the
renderer process in which it runs has died.
- The CefFrameHostImpl object representing the main frame will always be valid
but the underlying RFH (and associated frame ID) may change over time as a
result of cross-origin navigations. Despite these changes calling LoadURL on
the main frame object in the browser process will always navigate as expected.
- Speculative RFHs, which may be created as a result of a cross-origin
navigation and discarded if that navigation is not committed, are now handled
correctly (e.g. ignored in most cases until they're committed).
- It is less likely, but still possible, to receive a CefFrame object with an
invalid frame ID (ID < 0). This can happen in cases where a RFH has not yet
been created for a sub-frame. For example, when OnBeforeBrowse is called
before initiating navigation in a previously nonexisting sub-frame.
To test: All tests pass with NetworkService enabled and disabled.
