Idle cleanup for worker context

cc/output/context_cache_controller.cc

Index: cc/output/context_cache_controller.cc
diff --git a/cc/output/context_cache_controller.cc b/cc/output/context_cache_controller.cc
index 218059dd1780531bd90debf3b0f8884b5a92cb6a..4aa2f46789f2b3a97ef6c9f9b4b4dcf159571e08 100644
--- a/cc/output/context_cache_controller.cc
+++ b/cc/output/context_cache_controller.cc
@@ -7,17 +7,22 @@
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/single_thread_task_runner.h"
+#include "base/synchronization/lock.h"
 #include "gpu/command_buffer/client/context_support.h"
 #include "third_party/skia/include/gpu/GrContext.h"
 
 namespace cc {
-ContextCacheController::ScopedVisibility::ScopedVisibility() = default;
+namespace {
+static const int kIdleCleanupDelaySeconds = 1;
+}  // namespace
 
-ContextCacheController::ScopedVisibility::~ScopedVisibility() {
+ContextCacheController::ScopedToken::ScopedToken() = default;
+
+ContextCacheController::ScopedToken::~ScopedToken() {
   DCHECK(released_);
 }
 
-void ContextCacheController::ScopedVisibility::Release() {
+void ContextCacheController::ScopedToken::Release() {
   DCHECK(!released_);
   released_ = true;
 }
@@ -25,7 +30,10 @@ void ContextCacheController::ScopedVisibility::Release() {
 ContextCacheController::ContextCacheController(
     gpu::ContextSupport* context_support,
     scoped_refptr<base::SingleThreadTaskRunner> task_runner)
-    : context_support_(context_support), task_runner_(std::move(task_runner)) {}
+    : context_support_(context_support),
+      task_runner_(std::move(task_runner)),
+      idle_callback_(base::Bind(&ContextCacheController::OnIdle,
+                                base::Unretained(this))) {}
 
 ContextCacheController::~ContextCacheController() = default;
 
@@ -33,6 +41,10 @@ void ContextCacheController::SetGrContext(GrContext* gr_context) {
   gr_context_ = gr_context;
 }
 
+void ContextCacheController::SetLock(base::Lock* lock) {
+  context_lock_ = lock;
+}
+
 std::unique_ptr<ContextCacheController::ScopedVisibility>
 ContextCacheController::ClientBecameVisible() {
   bool became_visible = num_clients_visible_ == 0;
@@ -53,20 +65,56 @@ void ContextCacheController::ClientBecameNotVisible(
   --num_clients_visible_;
 
   if (num_clients_visible_ == 0) {
+    // We are freeing resources now - cancel any pending idle callbacks.
+    ++current_idle_generation_;
+
     if (gr_context_)
       gr_context_->freeGpuResources();
     context_support_->SetAggressivelyFreeResources(true);
   }
 }
 
-std::unique_ptr<ContextCacheController::ScopedVisibility>
-ContextCacheController::CreateScopedVisibilityForTesting() const {
-  return base::WrapUnique(new ScopedVisibility());
+std::unique_ptr<ContextCacheController::ScopedBusy>
+ContextCacheController::ClientBecameBusy() {
+  ++num_clients_busy_;
+  // We are busy, cancel any pending idle callbacks.
+  ++current_idle_generation_;
+
+  return base::WrapUnique(new ScopedBusy());
 }
 
-void ContextCacheController::ReleaseScopedVisibilityForTesting(
-    std::unique_ptr<ScopedVisibility> scoped_visibility) const {
-  scoped_visibility->Release();
+void ContextCacheController::ClientBecameNotBusy(
+    std::unique_ptr<ScopedBusy> scoped_busy) {
+  DCHECK(scoped_busy);
+  scoped_busy->Release();
+
+  DCHECK_GT(num_clients_busy_, 0u);
+  --num_clients_busy_;
+
+  // If we have become idle and we are visible, queue a task to drop resources
+  // after a delay. If are not visible, we have already dropped resources.
+  if (num_clients_busy_ == 0 && num_clients_visible_ > 0 && task_runner_) {
+    task_runner_->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(idle_callback_.callback(), current_idle_generation_),
+        base::TimeDelta::FromSeconds(kIdleCleanupDelaySeconds));
+  }
+}
+
+void ContextCacheController::OnIdle(uint32_t idle_generation) {
+  std::unique_ptr<base::AutoLock> hold;
+  if (context_lock_)
+    hold.reset(new base::AutoLock(*context_lock_));
+
+  if (current_idle_generation_ != idle_generation)
+    return;
+
+  if (gr_context_)
+    gr_context_->freeGpuResources();
+
+  // Toggle SetAggressivelyFreeResources to drop command buffer data.
+  context_support_->SetAggressivelyFreeResources(true);
+  context_support_->SetAggressivelyFreeResources(false);
 }
 
 }  // namespace cc