Allow the renderer process to map textures from one context into another.

content/renderer/gpu/renderer_gl_context.h

 // Copyright (c) 2011 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.
 
 // This API is consistent with other OpenGL setup APIs like window's WGL
 // and pepper's PGL. This API is used to manage OpenGL RendererGLContexts in the
 // Chrome renderer process in a way that is consistent with other platforms.
 
 #ifndef CONTENT_RENDERER_GPU_RENDERER_GL_CONTEXT_H_
 #define CONTENT_RENDERER_GPU_RENDERER_GL_CONTEXT_H_
 #pragma once
 
 #include "base/callback_old.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "build/build_config.h"
+#include "gpu/command_buffer/common/constants.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/size.h"
 
 class GpuChannelHost;
 class MessageLoop;
 class CommandBufferProxy;
 class GURL;
 class TransportTextureHost;
 
 namespace gpu {
@@ skipping 89 matching lines @@
   // same thread as the parent. A child RendererGLContext may not outlive its
   // parent.  attrib_list must be NULL or a NONE-terminated list of
   // attribute/value pairs.
   static RendererGLContext* CreateOffscreenContext(
       GpuChannelHost* channel,
       const gfx::Size& size,
       const char* allowed_extensions,
       const int32* attrib_list,
       const GURL& active_url);
 
+  // Map a resource from an external context into this context. The source
+  // context need not be in the same share group from the client's point of
+  // view, allowing safe sharing between an "untrusted" context, like Pepper
+  // and a compositor context.
+  //
+  // Currently only texture resources are supported. TODO(apatrick): generalize
+  // this as appropriate.
+  //
+  // To unmap a previously mapped external resource, delete it in the
+  // destination context group. This will not delete the underlying texture
+  // object, just disassociate it with the id in the destination context group.
+  //
+  // The lifetime of the external resource is managed by the context group it
+  // was originally created in. When the last context in that group is destroyed
+  // the resource becomes invalid in all other context groups it is mapped into.
+  bool MapExternalResource(gpu::resource_type::ResourceType resource_type,
+                           uint32 resource_source_id,
+                           RendererGLContext* source_context,
+                           uint32 resource_dest_id);
+
+  // TODO(apatrick): this is a workaround until the parent / child relationship
+  // between contexts is removed. MapExternalResource has no such restrictions
+  // on the relationship between contexts. Use it instead.
+  bool MapExternalResourceToParent(
+      gpu::resource_type::ResourceType resource_type,
+      uint32 resource_source_id,
+      uint32 resource_dest_id);
+
   // Sets the parent context. If any parent textures have been created for
   // another parent, it is important to delete them before changing the parent.
   bool SetParent(RendererGLContext* parent);
 
   // Resize an offscreen frame buffer. The resize occurs on the next call to
   // SwapBuffers. This is to avoid waiting until all pending GL calls have been
   // executed by the GPU process. Everything rendered up to the call to
   // SwapBuffers will be lost. A lost RendererGLContext will be reported if the
   // resize fails.
   void ResizeOffscreen(const gfx::Size& size);
@@ skipping 68 matching lines @@
   int32 transfer_buffer_id_;
   gpu::gles2::GLES2Implementation* gles2_implementation_;
   gfx::Size size_;
   Error last_error_;
   int frame_number_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererGLContext);
 };
 
 #endif  // CONTENT_RENDERER_GPU_RENDERER_GL_CONTEXT_H_