IPC: Make ChannelReader inherit from SupportsAttachmentBrokering.

Each IPC::Channel will have a reference to an AttachmentBroker. This is
accomplished by requiring each of the Channel::Create methods to have a
|broker| parameter. For now, the |broker| parameter has a default value of
nullptr. This default parameter only exists so that this CL and subsequent
refactors can be decomposed into smaller CLs. The default parameter will be
removed once all callers of Channel::Create have been updated to pass in an
appropriate broker.

BUG=493414

Review URL: https://codereview.chromium.org/1185133006

Cr-Commit-Position: refs/heads/master@{#334699}

1 files changed, 9 insertions, 2 deletions

diff --git a/ipc/ipc_channel_posix.h b/ipc/ipc_channel_posix.h
index 986eb8a..879adc3 100644
--- a/ipc/ipc_channel_posix.h
+++ b/ipc/ipc_channel_posix.h
@@ -26,14 +26,18 @@ class IPC_EXPORT ChannelPosix : public Channel,
                                 public internal::ChannelReader,
                                 public base::MessageLoopForIO::Watcher {
  public:
-  ChannelPosix(const IPC::ChannelHandle& channel_handle, Mode mode,
-               Listener* listener);
+  // |broker| must outlive the newly created object.
+  ChannelPosix(const IPC::ChannelHandle& channel_handle,
+               Mode mode,
+               Listener* listener,
+               AttachmentBroker* broker);
   ~ChannelPosix() override;
 
   // Channel implementation
   bool Connect() override;
   void Close() override;
   bool Send(Message* message) override;
+  AttachmentBroker* GetAttachmentBroker() override;
   base::ProcessId GetPeerPID() const override;
   base::ProcessId GetSelfPID() const override;
   int GetClientFileDescriptor() const override;
@@ -175,6 +179,9 @@ class IPC_EXPORT ChannelPosix : public Channel,
   static int global_pid_;
 #endif  // OS_LINUX
 
+  // |broker_| must outlive this instance.
+  AttachmentBroker* broker_;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(ChannelPosix);
 };