PPAPI: Make GLES2 calls resilient to bad/dead resources.

ppapi/shared_impl/ppb_graphics_3d_shared.h

 // 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.
 
 #ifndef PPAPI_SHARED_IMPL_GRAPHICS_3D_IMPL_H_
 #define PPAPI_SHARED_IMPL_GRAPHICS_3D_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ppapi/c/pp_completion_callback.h"
@@ skipping 41 matching lines @@
   virtual void UnmapTexSubImage2DCHROMIUM(const void* mem) OVERRIDE;
 
   gpu::gles2::GLES2Implementation* gles2_impl() {
     return gles2_impl_.get();
   }
 
   // Sends swap-buffers notification to the plugin.
   void SwapBuffersACK(int32_t pp_error);
 
  protected:
-  // ScopedNoLocking makes sure we don't try to lock again when we already have
-  // the proxy lock. This is used when we need to use the CommandBuffer
-  // (possibly via gles2_impl) but we already have the proxy lock. The
-  // CommandBuffer in the plugin side of the proxy will otherwise try to acquire
-  // the ProxyLock, causing a crash because we already own the lock. (Locks in
-  // Chromium are never recursive).
-  class ScopedNoLocking {
-   public:
-    explicit ScopedNoLocking(PPB_Graphics3D_Shared* graphics3d_shared)
-        : graphics3d_shared_(graphics3d_shared) {
-      graphics3d_shared_->PushAlreadyLocked();
-    }
-    ~ScopedNoLocking() {
-      graphics3d_shared_->PopAlreadyLocked();
-    }
-   private:
-    PPB_Graphics3D_Shared* graphics3d_shared_;  // Weak
-
-    DISALLOW_COPY_AND_ASSIGN(ScopedNoLocking);
-  };
-
-
   PPB_Graphics3D_Shared(PP_Instance instance);
   PPB_Graphics3D_Shared(const HostResource& host_resource);
   virtual ~PPB_Graphics3D_Shared();
 
   virtual gpu::CommandBuffer* GetCommandBuffer() = 0;
   virtual gpu::GpuControl* GetGpuControl() = 0;
   virtual int32 DoSwapBuffers() = 0;
 
   bool HasPendingSwap() const;
   bool CreateGLES2Impl(int32 command_buffer_size,
                        int32 transfer_buffer_size,
                        gpu::gles2::GLES2Implementation* share_gles2);
   void DestroyGLES2Impl();
 
  private:
-  // On the plugin side, we need to know that we already have the lock, so that
-  // we don't try to acquire it again. The default implementation does nothing;
-  // the Plugin side of the proxy must implement these.
-  friend class ScopedNoLocking;
-  virtual void PushAlreadyLocked();
-  virtual void PopAlreadyLocked();
-
-  // The VideoDecoder needs to be able to call Graphics3D Flush() after taking
-  // the proxy lock. Hence it needs access to ScopedNoLocking.
-  friend class PPB_VideoDecoder_Shared;
-
   scoped_ptr<gpu::gles2::GLES2CmdHelper> gles2_helper_;
   scoped_ptr<gpu::TransferBuffer> transfer_buffer_;
   scoped_ptr<gpu::gles2::GLES2Implementation> gles2_impl_;
 
   // Callback that needs to be executed when swap-buffers is completed.
   scoped_refptr<TrackedCallback> swap_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(PPB_Graphics3D_Shared);
 };
 
 }  // namespace ppapi
 
 #endif  // PPAPI_SHARED_IMPL_GRAPHICS_3D_IMPL_H_