Update Context Client Visibility to use Scoped Pattern

gpu/command_buffer/client/gles2_implementation.cc

 // Copyright (c) 2012 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.
 
 // A class to emulate GLES2 over command buffers.
 
 #include "gpu/command_buffer/client/gles2_implementation.h"
 
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
@@ skipping 14 matching lines @@
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/memory_allocator_dump.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/process_memory_dump.h"
 #include "base/trace_event/trace_event.h"
 #include "gpu/command_buffer/client/buffer_tracker.h"
 #include "gpu/command_buffer/client/gles2_cmd_helper.h"
 #include "gpu/command_buffer/client/gpu_control.h"
 #include "gpu/command_buffer/client/program_info_manager.h"
 #include "gpu/command_buffer/client/query_tracker.h"
+#include "gpu/command_buffer/client/scoped_visibility_impl.h"
 #include "gpu/command_buffer/client/shared_memory_limits.h"
 #include "gpu/command_buffer/client/transfer_buffer.h"
 #include "gpu/command_buffer/client/vertex_array_object_manager.h"
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
 #include "gpu/command_buffer/common/id_allocator.h"
 #include "gpu/command_buffer/common/sync_token.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/rect_f.h"
 
 #if defined(GPU_CLIENT_DEBUG)
@@ skipping 113 matching lines @@
           // use any extra for memory contrained devices (<=1GB).
           base::SysInfo::AmountOfPhysicalMemory() > 1024 * 1024 * 1024
               ? base::saturated_cast<uint32_t>(
                     base::SysInfo::AmountOfPhysicalMemory() / 20)
               : 0),
 #endif
       current_trace_stack_(0),
       gpu_control_(gpu_control),
       capabilities_(gpu_control->GetCapabilities()),
       aggressively_free_resources_(false),
+      visible_clients_(0),
       cached_extension_string_(nullptr),
       weak_ptr_factory_(this) {
   DCHECK(helper);
   DCHECK(transfer_buffer);
   DCHECK(gpu_control);
 
   std::stringstream ss;
   ss << std::hex << this;
   this_in_hex_ = ss.str();
 
@@ skipping 5676 matching lines @@
 
 uint64_t GLES2Implementation::ShareGroupTracingGUID() const {
   return share_group_->TracingGUID();
 }
 
 void GLES2Implementation::SetErrorMessageCallback(
     const base::Callback<void(const char*, int32_t)>& callback) {
   error_message_callback_ = callback;
 }
 
-void GLES2Implementation::SetClientVisible(int client_id, bool is_visible) {
-  if (is_visible) {
-    visible_clients_.insert(client_id);
-  } else {
-    auto found = visible_clients_.find(client_id);
-    if (found != visible_clients_.end())
-      visible_clients_.erase(found);
-  }
+std::unique_ptr<ContextSupport::ScopedVisibility>
+GLES2Implementation::ClientBecameVisible() {
+  ++visible_clients_;
+  return std::unique_ptr<gpu::ScopedVisibilityImpl>(
+      new gpu::ScopedVisibilityImpl(this));
+}
+
+void GLES2Implementation::ClientBecameNotVisible(
+    std::unique_ptr<ScopedVisibility> visibility) {
+  DCHECK_GT(visible_clients_, 0u);
+  --visible_clients_;
+  static_cast<ScopedVisibilityImpl*>(visibility.get())->Release(this);

[danakj, 2016/08/18 21:39:44]

I think maybe just define this class in this .cc file unless you're going to
make it a first class part of the API.

[ericrk, 2016/08/19 17:23:19]

Done.

 }
 
 bool GLES2Implementation::AnyClientsVisible() const {
-  return !visible_clients_.empty();
+  return visible_clients_ > 0;
 }
 
 void GLES2Implementation::SetLostContextCallback(
     const base::Closure& callback) {
   lost_context_callback_ = callback;
 }
 
 GLuint64 GLES2Implementation::InsertFenceSyncCHROMIUM() {
   const uint64_t release = gpu_control_->GenerateFenceSyncRelease();
   helper_->InsertFenceSyncCHROMIUM(release);
@@ skipping 1023 matching lines @@
   cached_extensions_.clear();
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/client/gles2_implementation_impl_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu