DisplayCompositor should enforce invariant that frame size and device scale factor are fixed

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>
@@ skipping 40 matching lines @@
   frame_index_ = surface->frame_index() + 1;
   previous_frame_surface_id_ = surface->surface_id();
   CompositorFrame& frame = active_frame_ ? *active_frame_ : *pending_frame_;
   surface->TakeLatencyInfo(&frame.metadata.latency_info);
   surface->TakeLatencyInfoFromPendingFrame(&frame.metadata.latency_info);
 }
 
 void Surface::QueueFrame(CompositorFrame frame, const DrawCallback& callback) {
   TakeLatencyInfoFromPendingFrame(&frame.metadata.latency_info);
 
+  if (!frame.render_pass_list.empty()) {
+    gfx::Size frame_size = frame.render_pass_list.back()->output_rect.size();
+    float device_scale_factor = frame.metadata.device_scale_factor;
+
+    SurfaceInfo surface_info(surface_id_, device_scale_factor, frame_size);
+
+    if (!surface_info_)
+      surface_info_ = surface_info;
+
+    if (surface_info_ != surface_info) {
+      DCHECK(factory_);
+      factory_->OnBadFrameReceived();
+      return;
+    }
+  }
+
   base::Optional<CompositorFrame> previous_pending_frame =
       std::move(pending_frame_);
   pending_frame_.reset();
 
   UpdateBlockingSurfaces(previous_pending_frame, frame);
 
   // Receive and track the resources referenced from the CompositorFrame
   // regardless of whether it's pending or active.
   factory_->ReceiveFromChild(frame.resource_list);
 
@@ skipping 268 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