Overlays: Remove special casing of primary overlay plane

cc/output/overlay_processor.cc

 // Copyright 2014 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 "cc/output/overlay_processor.h"
 
 #include "cc/output/output_surface.h"
 #include "cc/output/overlay_strategy_single_on_top.h"
 #include "cc/output/overlay_strategy_underlay.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/gfx/transform.h"
 
 namespace cc {
 
 OverlayProcessor::OverlayProcessor(OutputSurface* surface) : surface_(surface) {
 }
 
 void OverlayProcessor::Initialize() {
   DCHECK(surface_);
   OverlayCandidateValidator* validator =
       surface_->GetOverlayCandidateValidator();
   if (validator)
     validator->GetStrategies(&strategies_);
 }
 
 OverlayProcessor::~OverlayProcessor() {}
 
 void OverlayProcessor::ProcessForOverlays(

[achaulk, 2015/09/30 19:04:19]

This doesn't always get called, because there are situations where it can do
nothing, which will also stop rendering. I suggest you move the primary plane
add to DirectRenderer::DrawFrame

     RenderPassList* render_passes_in_draw_order,
     OverlayCandidateList* candidate_list) {
+  RenderPass* root_render_pass = render_passes_in_draw_order->back();
+  DCHECK(root_render_pass);
+
+  // If we had no validator, or it had no strategies, schedule no planes.
+  if (strategies_.empty())

[achaulk, 2015/09/30 19:04:19]

Having no strategies should be valid, but this will cause the list to not get
populated which means there will be no planes scheduled

[ccameron, 2015/10/01 18:59:31]

Moving the primary plane to DirectRenderer cleared this up.

+    return;
+
+  // Create the overlay candidate for the primary surface, and mark it as always
+  // handled.
+  OverlayCandidate primary_surface;
+  primary_surface.display_rect = gfx::RectF(root_render_pass->output_rect);

[achaulk, 2015/09/30 19:04:19]

This needs to be in texture coordinates, eg 0..1

While ignored by current implementations, it might not always be

[ccameron, 2015/10/01 18:59:31]

Are you sure -- display_rect is read in GLRenderer::ScheduleOverlays, and is
rounded to the nearest integer.

I suggest we delete one of display_rect and quad_rect_in_target_space, to
clarify things.

[achaulk, 2015/10/01 19:41:46]

Oh right, this one is pixel coordinates. You do need to set uv_rect to 0,0 & 1,1

I'm not actually sure what quad_rect_in_target_space is for

[ccameron, 2015/10/01 21:08:48]

That's done by the ctor at 
https://code.google.com/p/chromium/codesearch#chromium/src/cc/output/overlay_...

+  primary_surface.quad_rect_in_target_space = root_render_pass->output_rect;
+  primary_surface.use_output_surface_for_resource = true;
+  primary_surface.overlay_handled = true;
+  DCHECK(candidate_list->empty());
+  candidate_list->push_back(primary_surface);
+
   for (StrategyList::iterator it = strategies_.begin(); it != strategies_.end();
        ++it) {
     if ((*it)->Attempt(render_passes_in_draw_order, candidate_list,
                        surface_->device_scale_factor())) {
       return;
     }
   }
 }
 
 }  // namespace cc