Enforce constant size and device scale factor for surfaces

content/renderer/android/synchronous_compositor_frame_sink.cc

 // Copyright 2013 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 "content/renderer/android/synchronous_compositor_frame_sink.h"
 
 #include <vector>
 
 #include "base/auto_reset.h"
 #include "base/location.h"
@@ skipping 224 matching lines @@
     return;
   }
 
   cc::CompositorFrame submit_frame;
 
   if (in_software_draw_) {
     // The frame we send to the client is actually just the metadata. Preserve
     // the |frame| for the software path below.
     submit_frame.metadata = frame.metadata.Clone();
 
-    if (!root_local_surface_id_.is_valid()) {
-      root_local_surface_id_ = local_surface_id_allocator_->GenerateId();
-      child_local_surface_id_ = local_surface_id_allocator_->GenerateId();
-    }
-
-    display_->SetLocalSurfaceId(root_local_surface_id_,
-                                frame.metadata.device_scale_factor);
-
     // The layer compositor should be giving a frame that covers the
     // |sw_viewport_for_current_draw_| but at 0,0.
     gfx::Size child_size = sw_viewport_for_current_draw_.size();
     DCHECK(gfx::Rect(child_size) == frame.render_pass_list.back()->output_rect);
 
     // Make a size that covers from 0,0 and includes the area coming from the
     // layer compositor.
     gfx::Size display_size(sw_viewport_for_current_draw_.right(),
                            sw_viewport_for_current_draw_.bottom());
     display_->Resize(display_size);
 
+    if (!root_local_surface_id_.is_valid() || display_size_ != display_size ||
+        device_scale_factor_ != frame.metadata.device_scale_factor) {
+      root_local_surface_id_ = local_surface_id_allocator_->GenerateId();
+      display_size_ = display_size;
+      device_scale_factor_ = frame.metadata.device_scale_factor;
+    }
+
+    if (!child_local_surface_id_.is_valid() || child_size_ != child_size ||
+        device_scale_factor_ != frame.metadata.device_scale_factor) {
+      child_local_surface_id_ = local_surface_id_allocator_->GenerateId();
+      child_size_ = child_size;
+      device_scale_factor_ = frame.metadata.device_scale_factor;
+    }
+
+    display_->SetLocalSurfaceId(root_local_surface_id_,
+                                frame.metadata.device_scale_factor);
+
     // The offset for the child frame relative to the origin of the canvas being
     // drawn into.
     gfx::Transform child_transform;
     child_transform.Translate(
         gfx::Vector2dF(sw_viewport_for_current_draw_.OffsetFromOrigin()));
 
     // Make a root frame that embeds the frame coming from the layer compositor
     // and positions it based on the provided viewport.
     // TODO(danakj): We could apply the transform here instead of passing it to
     // the CompositorFrameSink client too? (We'd have to do the same for
     // hardware frames in SurfacesInstance?)
     cc::CompositorFrame embed_frame;
     embed_frame.metadata.begin_frame_ack = frame.metadata.begin_frame_ack;
+    embed_frame.metadata.device_scale_factor =
+        frame.metadata.device_scale_factor;
     embed_frame.render_pass_list.push_back(cc::RenderPass::Create());
 
     // The embedding RenderPass covers the entire Display's area.
     const auto& embed_render_pass = embed_frame.render_pass_list.back();
     embed_render_pass->SetNew(1, gfx::Rect(display_size),
                               gfx::Rect(display_size), gfx::Transform());
     embed_render_pass->has_transparent_background = false;
 
     // The RenderPass has a single SurfaceDrawQuad (and SharedQuadState for it).
     auto* shared_quad_state =
         embed_render_pass->CreateAndAppendSharedQuadState();
     auto* surface_quad =
         embed_render_pass->CreateAndAppendDrawQuad<cc::SurfaceDrawQuad>();
     shared_quad_state->SetAll(
         child_transform, gfx::Rect(child_size), gfx::Rect(child_size),
         gfx::Rect() /* clip_rect */, false /* is_clipped */, 1.f /* opacity */,
         SkBlendMode::kSrcOver, 0 /* sorting_context_id */);
     surface_quad->SetNew(
         shared_quad_state, gfx::Rect(child_size), gfx::Rect(child_size),
         cc::SurfaceId(kChildFrameSinkId, child_local_surface_id_),
         cc::SurfaceDrawQuadType::PRIMARY, nullptr);
 
-    child_support_->SubmitCompositorFrame(child_local_surface_id_,
-                                          std::move(frame));
-    root_support_->SubmitCompositorFrame(root_local_surface_id_,
-                                         std::move(embed_frame));
+    DCHECK(child_support_->SubmitCompositorFrame(child_local_surface_id_,

[danakj, 2017/05/19 19:00:59]

and here

[Saman Sami, 2017/05/19 19:26:46]

Done.

+                                                 std::move(frame)));
+    DCHECK(root_support_->SubmitCompositorFrame(root_local_surface_id_,
+                                                std::move(embed_frame)));
     display_->DrawAndSwap();
   } else {
     // For hardware draws we send the whole frame to the client so it can draw
     // the content in it.
     submit_frame = std::move(frame);
   }
 
   sync_client_->SubmitCompositorFrame(compositor_frame_sink_id_,
                                       std::move(submit_frame));
   DeliverMessages();
@@ skipping 161 matching lines @@
     const cc::ReturnedResourceArray& resources) {
   DCHECK(resources.empty());
   client_->ReclaimResources(resources);
 }
 
 void SynchronousCompositorFrameSink::WillDrawSurface(
     const cc::LocalSurfaceId& local_surface_id,
     const gfx::Rect& damage_rect) {}
 
 }  // namespace content