Mac Overlays: Add sandwich strategy

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_sandwich.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::RendererState::RendererState() : device_scale_factor(1) {}
+OverlayProcessor::RendererState::~RendererState() {}
+
 OverlayProcessor::OverlayProcessor(OutputSurface* surface) : surface_(surface) {
 }
 
 void OverlayProcessor::Initialize() {
   DCHECK(surface_);
 
   OverlayCandidateValidator* candidates =
       surface_->GetOverlayCandidateValidator();
   if (candidates) {
+#if defined(OS_MACOSX)

[ccameron, 2015/08/23 21:29:05]

Is this (the #ifdef) a reasonable way to go about this? Or would you prefer
something more dynamic.

I will not want to use the other strategies on Mac (Sandwich handles both).

[alexst (slow to review), 2015/08/24 15:07:02]

I hope to keep this platform agnostic. Maybe we could ask the output surface for
it's strategy list if possible? That way things will be hidden in the code
that's already OSX specific.

+    strategies_.push_back(
+        scoped_ptr<Strategy>(new OverlayStrategySandwich(candidates)));
+#else
     strategies_.push_back(
         scoped_ptr<Strategy>(new OverlayStrategySingleOnTop(candidates)));
     strategies_.push_back(
         scoped_ptr<Strategy>(new OverlayStrategyUnderlay(candidates)));
+#endif
   }
 }
 
 OverlayProcessor::~OverlayProcessor() {}
 
 void OverlayProcessor::ProcessForOverlays(
+    const OverlayProcessor::RendererState& renderer_state,
     RenderPassList* render_passes_in_draw_order,
     OverlayCandidateList* candidate_list) {
   for (StrategyList::iterator it = strategies_.begin(); it != strategies_.end();
        ++it) {
-    if ((*it)->Attempt(render_passes_in_draw_order, candidate_list))
+    if ((*it)->Attempt(renderer_state, render_passes_in_draw_order,
+                       candidate_list)) {
       return;
+    }
   }
 }
 
 }  // namespace cc