[cc] Pass on BeginFrameAcks from CompositorEBFS through RWHVAura, DFH.

content/browser/renderer_host/render_widget_host_impl.cc

 // Copyright (c) 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/renderer_host/render_widget_host_impl.h"
 
 #include <math.h>
 
 #include <set>
 #include <tuple>
@@ skipping 536 matching lines @@
                         OnQueueSyntheticGesture)
     IPC_MESSAGE_HANDLER(InputHostMsg_ImeCancelComposition,
                         OnImeCancelComposition)
     IPC_MESSAGE_HANDLER(ViewHostMsg_Close, OnClose)
     IPC_MESSAGE_HANDLER(ViewHostMsg_UpdateScreenRects_ACK,
                         OnUpdateScreenRectsAck)
     IPC_MESSAGE_HANDLER(ViewHostMsg_RequestMove, OnRequestMove)
     IPC_MESSAGE_HANDLER(ViewHostMsg_SetTooltipText, OnSetTooltipText)
     IPC_MESSAGE_HANDLER_GENERIC(ViewHostMsg_SwapCompositorFrame,
                                 OnSwapCompositorFrame(msg))
+    IPC_MESSAGE_HANDLER(ViewHostMsg_BeginFrameDidNotDraw,
+                        OnBeginFrameDidNotDraw)

[brianderson, 2017/03/13 22:55:39]

Here and elsewhere: Can you call this OnBeginFrameDidNotSwap? In the future it's
possible we split out draw from swap. In such a world, we'd want to send a
DidNotSwap message even if we already drew.

[Eric Seckler, 2017/03/14 11:13:41]

Done.

     IPC_MESSAGE_HANDLER(ViewHostMsg_UpdateRect, OnUpdateRect)
     IPC_MESSAGE_HANDLER(ViewHostMsg_SetCursor, OnSetCursor)
     IPC_MESSAGE_HANDLER(ViewHostMsg_TextInputStateChanged,
                         OnTextInputStateChanged)
     IPC_MESSAGE_HANDLER(ViewHostMsg_LockMouse, OnLockMouse)
     IPC_MESSAGE_HANDLER(ViewHostMsg_UnlockMouse, OnUnlockMouse)
     IPC_MESSAGE_HANDLER(ViewHostMsg_ShowDisambiguationPopup,
                         OnShowDisambiguationPopup)
     IPC_MESSAGE_HANDLER(ViewHostMsg_SelectionBoundsChanged,
                         OnSelectionBoundsChanged)
@@ skipping 1289 matching lines @@
        ++i) {
     rph->OnMessageReceived(*i);
     if (i->dispatch_error())
       rph->OnBadMessageReceived(*i);
   }
   messages_to_deliver_with_frame.clear();
 
   return true;
 }
 
+void RenderWidgetHostImpl::OnBeginFrameDidNotDraw(
+    const cc::BeginFrameAck& ack) {
+  if (view_)
+    view_->OnBeginFrameDidNotDraw(ack);

[brianderson, 2017/03/13 22:55:39]

Since this is conditional, should the state in the View tracking
latest_confirmed_begin_frame_sequence_number_ be tracked here instead?

Or at least initialized in RWHI::SetView?

[Eric Seckler, 2017/03/14 11:13:41]

I don't think we can track the lcbfsn in RWHI, since it doesn't know anything
about DFH.

A view is also never "reused", i.e. detached from a RWHI and then re-attached
later. It's always constructed for a single RWHI (a pointer to RWH/RWHI is
provided in constructor). Thus, I don't think resetting the tracking during
RWHI::SetView makes a difference.

It also sounded like Fady wants to get rid of skipping drawing in DFH, so maybe
we can remove the tracking of lcbfsn in the RWHVs soon anyway.

+}
+
 void RenderWidgetHostImpl::OnUpdateRect(
     const ViewHostMsg_UpdateRect_Params& params) {
   TRACE_EVENT0("renderer_host", "RenderWidgetHostImpl::OnUpdateRect");
   TimeTicks paint_start = TimeTicks::Now();
 
   // Update our knowledge of the RenderWidget's size.
   current_size_ = params.view_size;
 
   bool is_resize_ack =
       ViewHostMsg_UpdateRect_Flags::is_resize_ack(params.flags);
@@ skipping 638 matching lines @@
     // different from the receiver's.
     file_system_file.url =
         GURL(storage::GetIsolatedFileSystemRootURIString(
                  file_system_url.origin(), filesystem_id, std::string())
                  .append(register_name));
     file_system_file.filesystem_id = filesystem_id;
   }
 }
 
 }  // namespace content