cc: Introduce BeginFrame sequence numbers and acknowledgements.

content/browser/renderer_host/render_widget_host_view_aura.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_view_aura.h"
 
 #include <set>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 352 matching lines @@
                                                    bool is_guest_view_hack)
     : host_(RenderWidgetHostImpl::From(host)),
       window_(nullptr),
       in_shutdown_(false),
       in_bounds_changed_(false),
       popup_parent_host_view_(nullptr),
       popup_child_host_view_(nullptr),
       is_loading_(false),
       has_composition_text_(false),
       begin_frame_source_(nullptr),
+      oldest_incorporated_frame_(0),
       needs_begin_frames_(false),
       needs_flush_input_(false),
       added_frame_observer_(false),
       cursor_visibility_state_in_renderer_(UNKNOWN),
 #if defined(OS_WIN)
       legacy_render_widget_host_HWND_(nullptr),
       legacy_window_destroyed_(false),
       virtual_keyboard_requested_(false),
 #endif
       has_snapped_to_boundary_(false),
@@ skipping 286 matching lines @@
   if (needs_frame == added_frame_observer_)
     return;
 
   added_frame_observer_ = needs_frame;
   if (needs_frame)
     begin_frame_source_->AddObserver(this);
   else
     begin_frame_source_->RemoveObserver(this);
 }
 
-void RenderWidgetHostViewAura::OnBeginFrame(
-    const cc::BeginFrameArgs& args) {
+void RenderWidgetHostViewAura::OnBeginFrame(const cc::BeginFrameArgs& args) {
+  if (args.source_id != last_begin_frame_args_.source_id) {
+    // Consider us up to date up to the previous BeginFrame.
+    oldest_incorporated_frame_ =
+        args.sequence_number > 0 ? args.sequence_number - 1 : 0;
+  }
+
   needs_flush_input_ = false;
   host_->FlushInput();
   UpdateNeedsBeginFramesInternal();
   host_->Send(new ViewMsg_BeginFrame(host_->GetRoutingID(), args));
   last_begin_frame_args_ = args;
 }
 
 const cc::BeginFrameArgs& RenderWidgetHostViewAura::LastUsedBeginFrameArgs()
     const {
   return last_begin_frame_args_;
@@ skipping 237 matching lines @@
 
     start_edge_top.Scale(viewportToDIPScale);
     start_edge_bottom.Scale(viewportToDIPScale);
     end_edge_top.Scale(viewportToDIPScale);
     end_edge_bottom.Scale(viewportToDIPScale);
 
     selection.start.SetEdge(start_edge_top, start_edge_bottom);
     selection.end.SetEdge(end_edge_top, end_edge_bottom);
   }
 
+  uint64_t begin_frame_source_id = frame.metadata.begin_frame_source_id;
+  uint64_t begin_frame_number = frame.metadata.begin_frame_number;
+  uint64_t oldest_incorporated_frame = frame.metadata.oldest_incorporated_frame;
+
   delegated_frame_host_->SwapDelegatedFrame(compositor_frame_sink_id,
                                             std::move(frame));
   SelectionUpdated(selection.is_editable, selection.is_empty_text_form_control,
                    selection.start, selection.end);
+
+  // The CompositorFrame's updates were only incorporated if it wasn't skipped.
+  bool has_updates = false;
+  if (!delegated_frame_host_->skipped_frames()) {
+    oldest_incorporated_frame_ = oldest_incorporated_frame;
+    has_updates = true;
+  }
+
+  cc::BeginFrameAck ack(begin_frame_source_id, begin_frame_number,
+                        oldest_incorporated_frame_, 0, has_updates);
+  if (begin_frame_source_)
+    begin_frame_source_->DidFinishFrame(this, ack);
+}
+
+void RenderWidgetHostViewAura::OnBeginFrameDidNotDraw(cc::BeginFrameAck ack) {
+  // DelegatedFrameHost may have skipped the last frame(s).
+  ack.oldest_incorporated_frame = oldest_incorporated_frame_;
+  if (begin_frame_source_)
+    begin_frame_source_->DidFinishFrame(this, ack);
 }
 
 void RenderWidgetHostViewAura::ClearCompositorFrame() {
   delegated_frame_host_->ClearDelegatedFrame();
 }
 
 void RenderWidgetHostViewAura::DidStopFlinging() {
   selection_controller_client_->OnScrollCompleted();
 }
 
@@ skipping 1436 matching lines @@
 
 void RenderWidgetHostViewAura::SetPopupChild(
     RenderWidgetHostViewAura* popup_child_host_view) {
   popup_child_host_view_ = popup_child_host_view;
   event_handler_->SetPopupChild(
       popup_child_host_view,
       popup_child_host_view ? popup_child_host_view->event_handler() : nullptr);
 }
 
 }  // namespace content