Free worker context resources on idle.

cc/output/context_provider.h

 // Copyright (c) 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.
 
 #ifndef CC_OUTPUT_CONTEXT_PROVIDER_H_
 #define CC_OUTPUT_CONTEXT_PROVIDER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "cc/base/cc_export.h"
+#include "gpu/command_buffer/client/context_support.h"
 #include "gpu/command_buffer/common/capabilities.h"
 
 class GrContext;
 
 namespace base {
 class Lock;
 }
 
 namespace gpu {
 class ContextSupport;
 namespace gles2 { class GLES2Interface; }
 }
 
 namespace cc {
 struct ManagedMemoryPolicy;
 
 class ContextProvider : public base::RefCountedThreadSafe<ContextProvider> {
  public:
   // Hold an instance of this lock while using a context across multiple
   // threads. This only works for ContextProviders that will return a valid
   // lock from GetLock(), so is not always supported. Most use of
   // ContextProvider should be single-thread only on the thread that
   // BindToCurrentThread is run on.
-  class ScopedContextLock {
+  class CC_EXPORT ScopedContextLock {
    public:
-    explicit ScopedContextLock(ContextProvider* context_provider)
-        : context_provider_(context_provider),
-          context_lock_(*context_provider_->GetLock()) {
-      // Allow current thread to use |context_provider_|.
-      context_provider_->DetachFromThread();
-    }
-    ~ScopedContextLock() {
-      // Allow usage by thread for which |context_provider_| is bound to.
-      context_provider_->DetachFromThread();
-    }
+    explicit ScopedContextLock(ContextProvider* context_provider);
+    ~ScopedContextLock();
 
     gpu::gles2::GLES2Interface* ContextGL() {
       return context_provider_->ContextGL();
     }
 
    private:
     ContextProvider* const context_provider_;
     base::AutoLock context_lock_;
+    std::unique_ptr<gpu::ContextSupport::ScopedBusy> busy_;
   };
 
   // Bind the 3d context to the current thread. This should be called before
   // accessing the contexts. Calling it more than once should have no effect.
   // Once this function has been called, the class should only be accessed
   // from the same thread unless the function has some explicitly specified
   // rules for access on a different thread. See SetupLockOnMainThread(), which
   // can be used to provide access from multiple threads.
   virtual bool BindToCurrentThread() = 0;
 
@@ skipping 29 matching lines @@
   virtual base::Lock* GetLock() = 0;
 
  protected:
   friend class base::RefCountedThreadSafe<ContextProvider>;
   virtual ~ContextProvider() {}
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_CONTEXT_PROVIDER_H_