Replace context parenting by sharing through mailboxes

Instead of tying contexts together through the parenting mechanism, we can allow
the client to produce the front buffer of an offscreen context into a mailbox,
and use that in the "parent" context.
It simplifies the code and the semantics wrt lost contexts, and we want to use
mailboxes anyway.

BUG=164095

Review URL: https://chromiumcodereview.appspot.com/15798014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@204194 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 4 insertions, 6 deletions

diff --git a/gpu/ipc/command_buffer_proxy.h b/gpu/ipc/command_buffer_proxy.h
index a992369..d33eae4 100644
--- a/gpu/ipc/command_buffer_proxy.h
+++ b/gpu/ipc/command_buffer_proxy.h
@@ -10,6 +10,7 @@
 #include "base/callback.h"
 #include "gpu/command_buffer/common/command_buffer.h"
 #include "gpu/command_buffer/common/command_buffer_shared.h"
+#include "gpu/command_buffer/common/mailbox.h"
 
 // Client side proxy that forwards messages synchronously to a
 // CommandBufferStub.
@@ -28,12 +29,9 @@ class GPU_EXPORT CommandBufferProxy : public gpu::CommandBuffer {
   // the task whether the echo succeeds or not.
   virtual bool Echo(const base::Closure& callback) = 0;
 
-  // Reparent a command buffer. TODO(apatrick): going forward, the notion of
-  // the parent / child relationship between command buffers is going away in
-  // favor of the notion of surfaces that can be drawn to in one command buffer
-  // and bound as a texture in any other.
-  virtual bool SetParent(CommandBufferProxy* parent_command_buffer,
-                         uint32 parent_texture_id) = 0;
+  // For offscreen contexts, produces the front buffer into a newly created
+  // mailbox.
+  virtual bool ProduceFrontBuffer(const gpu::Mailbox& mailbox) = 0;
 
   virtual void SetChannelErrorCallback(const base::Closure& callback) = 0;