Make channel preemption not require view contexts for hookup

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index a4b3eda71ad9ff4919d3ab0323a72b21cc5cc29e..1e5f5374d0e47d8e7817db8a39815187511f1730 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -309,9 +309,6 @@ void RenderWidgetHostImpl::SetView(RenderWidgetHostViewBase* view) {
                                            view_->GetSurfaceIdNamespace()));
   }
 
-  GpuSurfaceTracker::Get()->SetSurfaceHandle(
-      surface_id_, GetCompositingSurface());
-
   synthetic_gesture_controller_.reset();
 }
 
@@ -337,12 +334,6 @@ gfx::NativeViewId RenderWidgetHostImpl::GetNativeViewId() const {
   return 0;
 }
 
-gfx::GLSurfaceHandle RenderWidgetHostImpl::GetCompositingSurface() {
-  if (view_)
-    return view_->GetCompositingSurface();
-  return gfx::GLSurfaceHandle();
-}
-
 void RenderWidgetHostImpl::ResetSizeAndRepaintPendingFlags() {
   resize_ack_pending_ = false;
   if (repaint_ack_pending_) {
@@ -396,9 +387,6 @@ void RenderWidgetHostImpl::Init() {
 
   renderer_initialized_ = true;
 
-  GpuSurfaceTracker::Get()->SetSurfaceHandle(
-      surface_id_, GetCompositingSurface());

[no sievers, 2015/09/23 21:53:21]

It looks to me like removing this would possibly also allow us to remove the
deferred logic to start the compositor in RenderWidget, which is for new widgets
created by the renderer (see RenderWiget::CompleteInit() and StartCompositor()).
Maybe put a TODO over there if you agree, so we can attempt this separately (it
might of course expose some other bug/race).

[piman, 2015/09/23 23:33:37]

Added a TODO and filed a bug. I thought we still relied on it, but I can't find
the code to match, so it needs investigation, and we may be able to remove.

-
   // Send the ack along with the information on placement.
   Send(new ViewMsg_CreatingNew_ACK(routing_id_));
   GetProcess()->ResumeRequestsForView(routing_id_);
@@ -1273,8 +1261,6 @@ void RenderWidgetHostImpl::RendererExited(base::TerminationStatus status,
   StopHangMonitorTimeout();
 
   if (view_) {
-    GpuSurfaceTracker::Get()->SetSurfaceHandle(surface_id_,
-                                               gfx::GLSurfaceHandle());
     view_->RenderProcessGone(status, exit_code);
     view_ = nullptr;  // The View should be deleted by RenderProcessGone.
     view_weak_.reset();