Resize output_rect of aggregated CompositorFrame to enable it to be drawn when resizing.

cc/surfaces/display.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/display.h"
 
 #include "base/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/debug/benchmark_instrumentation.h"
 #include "cc/output/compositor_frame.h"
@@ skipping 200 matching lines @@
                                       stored_latency_info_.end());
   stored_latency_info_.clear();
   bool have_copy_requests = false;
   for (const auto* pass : frame_data->render_pass_list) {
     have_copy_requests |= !pass->copy_requests.empty();
   }
 
   gfx::Size surface_size;
   bool have_damage = false;
   if (!frame_data->render_pass_list.empty()) {
-    surface_size = frame_data->render_pass_list.back()->output_rect.size();
-    have_damage =
-        !frame_data->render_pass_list.back()->damage_rect.size().IsEmpty();
+    RenderPass& last_render_pass = *frame_data->render_pass_list.back();
+    if (last_render_pass.output_rect.size() != current_surface_size_ &&
+        last_render_pass.damage_rect == last_render_pass.output_rect &&
+        !current_surface_size_.IsEmpty()) {
+      // Resize the output rect to the current surface size so that we won't
+      // skip the draw and so that the GL swap won't stretch the output.
+      last_render_pass.output_rect.set_size(current_surface_size_);
+      last_render_pass.damage_rect = last_render_pass.output_rect;
+    }
+    surface_size = last_render_pass.output_rect.size();
+    have_damage = !last_render_pass.damage_rect.size().IsEmpty();
   }
 
   bool size_matches = surface_size == current_surface_size_;
   if (!size_matches)
-    TRACE_EVENT_INSTANT0("cc", "Size missmatch.", TRACE_EVENT_SCOPE_THREAD);
+    TRACE_EVENT_INSTANT0("cc", "Size mismatch.", TRACE_EVENT_SCOPE_THREAD);

[brianderson, 2015/11/04 01:40:25]

In what cases would we hit this trace after this patch?

 
   bool should_draw = !frame->metadata.latency_info.empty() ||
                      have_copy_requests || (have_damage && size_matches);
 
   // If the surface is suspended then the resources to be used by the draw are
   // likely destroyed.
   if (output_surface_->SurfaceIsSuspendForRecycle()) {
     TRACE_EVENT_INSTANT0("cc", "Surface is suspended for recycle.",
                          TRACE_EVENT_SCOPE_THREAD);
     should_draw = false;
@@ skipping 113 matching lines @@
 
   if (surface_id == current_surface_id_)
     UpdateRootSurfaceResourcesLocked();
 }
 
 SurfaceId Display::CurrentSurfaceId() {
   return current_surface_id_;
 }
 
 }  // namespace cc