ChannelMojo Refactoring: Merge MessageReader into MessagePipeReader

MessageReader was the sole subclass  of MessageReader.
There is no need to have two classes.
This CL also decouple ChannelMojo from MessagePipeReader
through a delegate interface.

R=viettrungluu@chromium.org
BUG=377980

Review URL: https://codereview.chromium.org/750673002

Cr-Commit-Position: refs/heads/master@{#305728}

1 files changed, 21 insertions, 9 deletions

diff --git a/ipc/mojo/ipc_message_pipe_reader.h b/ipc/mojo/ipc_message_pipe_reader.h
index ecfa018..ee1d3b5 100644
--- a/ipc/mojo/ipc_message_pipe_reader.h
+++ b/ipc/mojo/ipc_message_pipe_reader.h
@@ -7,7 +7,9 @@
 
 #include <vector>
 
+#include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
+#include "ipc/ipc_message.h"
 #include "mojo/public/c/environment/async_waiter.h"
 #include "mojo/public/cpp/system/core.h"
 
@@ -30,6 +32,13 @@ namespace internal {
 //
 class MessagePipeReader {
  public:
+  class Delegate {
+   public:
+    virtual void OnMessageReceived(Message& message) = 0;
+    virtual void OnPipeClosed(MessagePipeReader* reader) = 0;
+    virtual void OnPipeError(MessagePipeReader* reader) = 0;
+  };
+
   // Delay the object deletion using the current message loop.
   // This is intended to used by MessagePipeReader owners.
   class DelayedDeleter {
@@ -39,13 +48,16 @@ class MessagePipeReader {
     static void DeleteNow(MessagePipeReader* ptr) { delete ptr; }
 
     DelayedDeleter() {}
-    DelayedDeleter(const DefaultType&) {}
+    explicit DelayedDeleter(const DefaultType&) {}
     DelayedDeleter& operator=(const DefaultType&) { return *this; }
 
     void operator()(MessagePipeReader* ptr) const;
   };
 
-  explicit MessagePipeReader(mojo::ScopedMessagePipeHandle handle);
+  // Both parameters must be non-null.
+  // Build a reader that reads messages from |handle| and lets |delegate| know.
+  // Note that MessagePipeReader doesn't delete |delete|.
+  MessagePipeReader(mojo::ScopedMessagePipeHandle handle, Delegate* delegate);
   virtual ~MessagePipeReader();
 
   MojoHandle handle() const { return pipe_.get().value(); }
@@ -68,17 +80,15 @@ class MessagePipeReader {
   // Return true if the MessagePipe is alive.
   bool IsValid() { return pipe_.is_valid(); }
 
-  //
-  // The client have to implment these callback to get the readiness
-  // event from the reader
-  //
-  virtual void OnMessageReceived() = 0;
-  virtual void OnPipeClosed() = 0;
-  virtual void OnPipeError(MojoResult error) = 0;
+  bool Send(scoped_ptr<Message> message);
 
  private:
   static void InvokePipeIsReady(void* closure, MojoResult result);
 
+  void OnMessageReceived();
+  void OnPipeClosed();
+  void OnPipeError(MojoResult error);
+
   MojoResult ReadMessageBytes();
   void PipeIsReady(MojoResult wait_result);
   void StartWaiting();
@@ -88,6 +98,8 @@ class MessagePipeReader {
   std::vector<MojoHandle> handle_buffer_;
   MojoAsyncWaitID pipe_wait_id_;
   mojo::ScopedMessagePipeHandle pipe_;
+  // Is null once the message pipe is closed.
+  Delegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePipeReader);
 };