Avoid destroying surface before the parent surface stops referencing it.

ui/compositor/compositor.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 "ui/compositor/compositor.h"
 
 #include <algorithm>
 #include <deque>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_util.h"
 #include "base/sys_info.h"
 #include "cc/base/latency_info_swap_promise.h"
 #include "cc/base/switches.h"
 #include "cc/input/input_handler.h"
 #include "cc/layers/layer.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/output/context_provider.h"
+#include "cc/surfaces/surface_id_allocator.h"
 #include "cc/trees/layer_tree_host.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/compositor/compositor_observer.h"
 #include "ui/compositor/compositor_switches.h"
 #include "ui/compositor/compositor_vsync_manager.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animator_collection.h"
 #include "ui/gfx/frame_time.h"
 #include "ui/gl/gl_context.h"
@@ skipping 28 matching lines @@
   compositor_->UnlockCompositor();
   compositor_ = NULL;
 }
 
 }  // namespace ui
 
 namespace {}  // namespace
 
 namespace ui {
 
+class SatisfySwapPromise : public cc::SwapPromise {
+ public:
+  explicit SatisfySwapPromise(uint32_t id) : id_(id) {}
+
+ private:
+  virtual void DidSwap(cc::CompositorFrameMetadata* metadata) OVERRIDE {
+    metadata->satisfies_sequences.push_back(id_);
+  }
+
+  virtual void DidNotSwap(DidNotSwapReason reason) OVERRIDE {
+    // TODO: Send to the SurfaceManager immediately.

[danakj, 2014/10/02 01:53:45]

put a name on the todo

+    DCHECK(false);
+  }
+  virtual int64 TraceId() const OVERRIDE { return 0; }
+  uint32_t id_;
+};
+
 Compositor::Compositor(gfx::AcceleratedWidget widget,
                        ui::ContextFactory* context_factory,
                        scoped_refptr<base::SingleThreadTaskRunner> task_runner)
     : context_factory_(context_factory),
       root_layer_(NULL),
       widget_(widget),
+      surface_id_allocator_(context_factory->CreateSurfaceIdAllocator()),
+      surface_sequence_number_(0),
       compositor_thread_loop_(context_factory->GetCompositorMessageLoop()),
       task_runner_(task_runner),
       vsync_manager_(new CompositorVSyncManager()),
       device_scale_factor_(0.0f),
       last_started_frame_(0),
       last_ended_frame_(0),
       disable_schedule_composite_(false),
       compositor_lock_(NULL),
       defer_draw_scheduling_(false),
       waiting_on_compositing_end_(false),
@@ skipping 313 matching lines @@
 
 const cc::LayerTreeDebugState& Compositor::GetLayerTreeDebugState() const {
   return host_->debug_state();
 }
 
 void Compositor::SetLayerTreeDebugState(
     const cc::LayerTreeDebugState& debug_state) {
   host_->SetDebugState(debug_state);
 }
 
+cc::SurfaceSequence Compositor::CreateSurfaceSequence() {

[danakj, 2014/10/09 00:23:52]

Can you give this a name that says its going to use that sequence number in the
next compositor frame as well. I think that's the important part to capture
rather than just a name.

+  cc::SurfaceSequence sequence;
+  sequence.id_namespace = surface_id_allocator_->id_namespace();
+  sequence.sequence = ++surface_sequence_number_;
+  scoped_ptr<cc::SwapPromise> promise(
+      new SatisfySwapPromise(surface_sequence_number_));
+  host_->QueueSwapPromise(promise.Pass());
+  return sequence;
+}
+
 scoped_refptr<CompositorLock> Compositor::GetCompositorLock() {
   if (!compositor_lock_) {
     compositor_lock_ = new CompositorLock(this);
     if (compositor_thread_loop_.get())
       host_->SetDeferCommits(true);
     FOR_EACH_OBSERVER(CompositorObserver,
                       observer_list_,
                       OnCompositingLockStateChanged(this));
   }
   return compositor_lock_;
@@ skipping 24 matching lines @@
     // Call ScheduleDraw() instead of Draw() in order to allow other
     // CompositorObservers to be notified before starting another
     // draw cycle.
     ScheduleDraw();
   }
   FOR_EACH_OBSERVER(
       CompositorObserver, observer_list_, OnCompositingEnded(this));
 }
 
 }  // namespace ui