Enforce constant size and device scale factor for surfaces

cc/surfaces/surface.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/surfaces/surface.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
 
 #include "base/stl_util.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/surfaces/local_surface_id_allocator.h"
 #include "cc/surfaces/pending_frame_observer.h"
 #include "cc/surfaces/surface_factory.h"
 #include "cc/surfaces/surface_manager.h"
 
 namespace cc {
 
 // The frame index starts at 2 so that empty frames will be treated as
 // completely damaged the first time they're drawn from.
 static const int kFrameIndexStart = 2;
 
-Surface::Surface(const SurfaceId& id, base::WeakPtr<SurfaceFactory> factory)
-    : surface_id_(id),
-      previous_frame_surface_id_(id),
+Surface::Surface(const SurfaceInfo& info, base::WeakPtr<SurfaceFactory> factory)
+    : surface_info_(info),
+      previous_frame_surface_id_(info.id()),
       factory_(factory),
       frame_index_(kFrameIndexStart),
       destroyed_(false) {}
 
 Surface::~Surface() {
   ClearCopyRequests();
   for (auto& observer : observers_)
     observer.OnSurfaceDiscarded(this);
   observers_.Clear();
 
   UnrefFrameResourcesAndRunDrawCallback(std::move(pending_frame_data_));
   UnrefFrameResourcesAndRunDrawCallback(std::move(active_frame_data_));
 }
 
 void Surface::SetPreviousFrameSurface(Surface* surface) {
   DCHECK(surface && (HasActiveFrame() || HasPendingFrame()));
   frame_index_ = surface->frame_index() + 1;
   previous_frame_surface_id_ = surface->surface_id();
   CompositorFrame& frame = active_frame_data_ ? active_frame_data_->frame
                                               : pending_frame_data_->frame;
   surface->TakeLatencyInfo(&frame.metadata.latency_info);
   surface->TakeLatencyInfoFromPendingFrame(&frame.metadata.latency_info);
 }
 
 void Surface::QueueFrame(CompositorFrame frame,
                          const DrawCallback& callback,
                          const WillDrawCallback& will_draw_callback) {
+  if (!frame.render_pass_list.empty()) {

[Fady Samuel, 2017/05/07 18:16:51]

Not necessary any more right?

[Saman Sami, 2017/05/08 20:40:32]

Done.

+    gfx::Size frame_size = frame.render_pass_list.back()->output_rect.size();
+    float device_scale_factor = frame.metadata.device_scale_factor;
+    if (frame_size != surface_info_.size_in_pixels() ||
+        device_scale_factor != surface_info_.device_scale_factor()) {

[Fady Samuel, 2017/05/01 20:36:54]

Return resources and call the callback too.

[Fady Samuel, 2017/05/07 18:16:51]

I'd love to move this test into a common place because we do it...EVERYWHERE,
and we're talking about adding more things to SurfaceInfo.

Maybe a CompositorFrame::Matches(...)? Or SurfaceInfo::Matches(...)

[Saman Sami, 2017/05/08 20:40:32]

That'll be nice, yes.

[Saman Sami, 2017/05/16 18:55:46]

Actually, I'm not sure how much that will help. I know we have the comparison
for new size vs old size all over the code base, but we rarely have a
SurfaceInfo object, perhaps because we usually keep a LocalSurfaceId as opposed
to a full SurfaceId which is necessary for SurfaceInfo.

+      DLOG(ERROR) << "Frame size doesn't match surface size.";
+      return;
+    }
+  }
+
   TakeLatencyInfoFromPendingFrame(&frame.metadata.latency_info);
 
   base::Optional<FrameData> previous_pending_frame_data =
       std::move(pending_frame_data_);
   pending_frame_data_.reset();
 
   UpdateBlockingSurfaces(previous_pending_frame_data.has_value(), frame);
 
   // Receive and track the resources referenced from the CompositorFrame
   // regardless of whether it's pending or active.
@@ skipping 214 matching lines @@
     DrawCallback callback = active_frame_data_->draw_callback;
     active_frame_data_->draw_callback = DrawCallback();
     callback.Run();
   }
 }
 
 void Surface::RunWillDrawCallback(const gfx::Rect& damage_rect) {
   if (!active_frame_data_ || active_frame_data_->will_draw_callback.is_null())
     return;
 
-  active_frame_data_->will_draw_callback.Run(surface_id_.local_surface_id(),
+  active_frame_data_->will_draw_callback.Run(surface_id().local_surface_id(),
                                              damage_rect);
 }
 
 void Surface::AddDestructionDependency(SurfaceSequence sequence) {
   destruction_dependencies_.push_back(sequence);
 }
 
 void Surface::SatisfyDestructionDependencies(
     std::unordered_set<SurfaceSequence, SurfaceSequenceHash>* sequences,
     std::unordered_set<FrameSinkId, FrameSinkIdHash>* valid_frame_sink_ids) {
@@ skipping 45 matching lines @@
     frame->metadata.latency_info.swap(*latency_info);
     return;
   }
   std::copy(frame->metadata.latency_info.begin(),
             frame->metadata.latency_info.end(),
             std::back_inserter(*latency_info));
   frame->metadata.latency_info.clear();
 }
 
 }  // namespace cc