aw: Share cc::Display instance

android_webview/browser/surfaces_instance.cc

+// Copyright 2016 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 "android_webview/browser/surfaces_instance.h"
+
+#include <utility>
+
+#include "android_webview/browser/aw_gl_surface.h"
+#include "android_webview/browser/aw_render_thread_context_provider.h"
+#include "android_webview/browser/deferred_gpu_command_service.h"
+#include "android_webview/browser/parent_output_surface.h"
+#include "base/lazy_instance.h"
+#include "base/memory/ptr_util.h"
+#include "cc/output/renderer_settings.h"
+#include "cc/output/texture_mailbox_deleter.h"
+#include "cc/quads/surface_draw_quad.h"
+#include "cc/scheduler/begin_frame_source.h"
+#include "cc/surfaces/display.h"
+#include "cc/surfaces/display_scheduler.h"
+#include "cc/surfaces/surface_factory.h"
+#include "cc/surfaces/surface_id_allocator.h"
+#include "cc/surfaces/surface_manager.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/size.h"
+#include "ui/gfx/transform.h"
+
+namespace android_webview {
+
+namespace {
+base::LazyInstance<base::WeakPtr<SurfacesInstance>>::Leaky g_surfaces_instance;
+}  // namespace
+
+// static
+scoped_refptr<SurfacesInstance> SurfacesInstance::GetOrCreateInstance() {

[boliu, 2016/06/23 23:27:08]

So the problem is that I want a singleton that's destroyed when it's not being
used, because it's using a lot of memory. Everything is on one thread, so no
thread safety issues here.

And the solution I came up with: refcounted singleton, that has a weakptr to
detect if been cleaned up already.

Thoughts? Is this evil? Is there already an pattern for this?

+  scoped_refptr<SurfacesInstance> instance(g_surfaces_instance.Get().get());
+  if (instance)
+    return instance;
+
+  instance = new SurfacesInstance;
+  g_surfaces_instance.Get() = instance->weak_ptr_factory_.GetWeakPtr();
+  return instance;
+}
+
+SurfacesInstance::SurfacesInstance()
+  : next_surface_id_namespace_(1u),
+    gl_surface_(new AwGLSurface),
+    weak_ptr_factory_(this) {
+  cc::RendererSettings settings;
+
+  // Should be kept in sync with compositor_impl_android.cc.
+  settings.allow_antialiasing = false;
+  settings.highp_threshold_min = 2048;
+
+  // Webview does not own the surface so should not clear it.
+  settings.should_clear_root_render_pass = false;
+
+  surface_manager_.reset(new cc::SurfaceManager);
+  surface_id_allocator_.reset(
+      new cc::SurfaceIdAllocator(next_surface_id_namespace_++));
+  surface_id_allocator_->RegisterSurfaceIdNamespace(surface_manager_.get());
+
+  std::unique_ptr<cc::BeginFrameSource> begin_frame_source(
+      new cc::StubBeginFrameSource);
+  std::unique_ptr<cc::TextureMailboxDeleter> texture_mailbox_deleter(
+      new cc::TextureMailboxDeleter(nullptr));
+  std::unique_ptr<ParentOutputSurface> output_surface_holder(
+      new ParentOutputSurface(AwRenderThreadContextProvider::Create(
+          gl_surface_, DeferredGpuCommandService::GetInstance())));
+  output_surface_ = output_surface_holder.get();
+  std::unique_ptr<cc::DisplayScheduler> scheduler(new cc::DisplayScheduler(
+      begin_frame_source.get(), nullptr,
+      output_surface_holder->capabilities().max_frames_pending));
+  display_.reset(new cc::Display(
+      surface_manager_.get(), nullptr /* shared_bitmap_manager */,
+      nullptr /* gpu_memory_buffer_manager */, settings,
+      surface_id_allocator_->id_namespace(), std::move(begin_frame_source),
+      std::move(output_surface_holder), std::move(scheduler),
+      std::move(texture_mailbox_deleter)));
+  display_->Initialize(this);
+
+  surface_factory_.reset(new cc::SurfaceFactory(surface_manager_.get(), this));
+}
+
+SurfacesInstance::~SurfacesInstance() {
+  if (!root_id_.is_null())
+    surface_factory_->Destroy(root_id_);
+}
+
+std::unique_ptr<cc::SurfaceIdAllocator>
+SurfacesInstance::CreateSurfaceIdAllocator() {
+  std::unique_ptr<cc::SurfaceIdAllocator> allocator = base::WrapUnique(
+      new cc::SurfaceIdAllocator(next_surface_id_namespace_++));
+  allocator->RegisterSurfaceIdNamespace(surface_manager_.get());
+  return allocator;
+}
+
+cc::SurfaceManager* SurfacesInstance::GetSurfaceManager() {
+  return surface_manager_.get();
+}
+
+void SurfacesInstance::SetBackingFrameBufferObject(
+    int framebuffer_binding_ext) {
+  gl_surface_->SetBackingFrameBufferObject(framebuffer_binding_ext);
+}
+
+void SurfacesInstance::DrawAndSwap(const gfx::Size& viewport,
+                                   const gfx::Rect& clip,
+                                   const gfx::Transform& transform,
+                                   const gfx::Size& frame_size,
+                                   const cc::SurfaceId& child_id,
+                                   const ScopedAppGLStateRestore& gl_state) {
+  // Create a frame with a single SurfaceDrawQuad referencing the child
+  // Surface and transformed using the given transform.
+  std::unique_ptr<cc::RenderPass> render_pass = cc::RenderPass::Create();
+  render_pass->SetAll(cc::RenderPassId(1, 1), gfx::Rect(viewport), clip,
+                      gfx::Transform(), false);
+
+  cc::SharedQuadState* quad_state =
+      render_pass->CreateAndAppendSharedQuadState();
+  quad_state->quad_to_target_transform = transform;
+  quad_state->quad_layer_bounds = frame_size;
+  quad_state->visible_quad_layer_rect = gfx::Rect(frame_size);
+  quad_state->opacity = 1.f;
+
+  cc::SurfaceDrawQuad* surface_quad =
+      render_pass->CreateAndAppendDrawQuad<cc::SurfaceDrawQuad>();
+  surface_quad->SetNew(quad_state, gfx::Rect(quad_state->quad_layer_bounds),
+                       gfx::Rect(quad_state->quad_layer_bounds), child_id);
+
+  std::unique_ptr<cc::DelegatedFrameData> delegated_frame(
+      new cc::DelegatedFrameData);
+  delegated_frame->render_pass_list.push_back(std::move(render_pass));
+  std::unique_ptr<cc::CompositorFrame> frame(new cc::CompositorFrame);
+  frame->delegated_frame_data = std::move(delegated_frame);
+
+  if (root_id_.is_null()) {
+    root_id_ = surface_id_allocator_->GenerateId();
+    surface_factory_->Create(root_id_);
+    display_->SetSurfaceId(root_id_, 1.f);
+  }
+  surface_factory_->SubmitCompositorFrame(root_id_, std::move(frame),
+                                          cc::SurfaceFactory::DrawCallback());
+
+  output_surface_->SetGLState(gl_state);
+  display_->Resize(viewport);
+  display_->SetExternalClip(clip);
+  display_->DrawAndSwap();
+
+  // TODO(boliu): member vars
+  std::unique_ptr<cc::CompositorFrame> empty_frame(new cc::CompositorFrame);
+  empty_frame->delegated_frame_data =
+      base::WrapUnique(new cc::DelegatedFrameData);
+  surface_factory_->SubmitCompositorFrame(root_id_, std::move(empty_frame),
+                                          cc::SurfaceFactory::DrawCallback());
+}
+
+void SurfacesInstance::ReturnResources(
+    const cc::ReturnedResourceArray& resources) {
+  // Root surface should have no resources to return.
+  CHECK(resources.empty());
+}
+
+void SurfacesInstance::SetBeginFrameSource(
+    cc::BeginFrameSource* begin_frame_source) {
+  // Parent compsitor calls DrawAndSwap directly and doesn't use
+  // BeginFrameSource.
+}
+
+}  // namespace android_webview