Mojo: Use new message APIs to reduce copying

mojo/public/cpp/system/handle.h

 // Copyright 2014 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 MOJO_PUBLIC_CPP_SYSTEM_HANDLE_H_
 #define MOJO_PUBLIC_CPP_SYSTEM_HANDLE_H_
 
 #include <stdint.h>
 #include <limits>
 
@@ skipping 106 matching lines @@
 
   void reset(HandleType handle = HandleType()) {
     CloseIfNecessary();
     handle_ = handle;
   }
 
   bool is_valid() const { return handle_.is_valid(); }
 
  private:
   void CloseIfNecessary() {
-    if (!handle_.is_valid())
-      return;
-    MojoResult result = MojoClose(handle_.value());
-    ALLOW_UNUSED_LOCAL(result);
-    DCHECK_EQ(MOJO_RESULT_OK, result);
+    if (handle_.is_valid())
+      handle_.Close();
   }
 
   HandleType handle_;
 };
 
 template <typename HandleType>
 inline ScopedHandleBase<HandleType> MakeScopedHandle(HandleType handle) {
   return ScopedHandleBase<HandleType>(handle);
 }
 
@@ skipping 13 matching lines @@
     value_ = other.value_;
     other.value_ = temp;
   }
 
   bool is_valid() const { return value_ != kInvalidHandleValue; }
 
   const MojoHandle& value() const { return value_; }
   MojoHandle* mutable_value() { return &value_; }
   void set_value(MojoHandle value) { value_ = value; }
 
+  void Close() {
+    DCHECK(is_valid());
+    MojoResult result = MojoClose(value_);
+    ALLOW_UNUSED_LOCAL(result);
+    DCHECK_EQ(MOJO_RESULT_OK, result);
+  }
+
  private:
   MojoHandle value_;
 
   // Copying and assignment allowed.
 };
 
 // Should have zero overhead.
 static_assert(sizeof(Handle) == sizeof(MojoHandle), "Bad size for C++ Handle");
 
 // The scoper should also impose no more overhead.
@@ skipping 116 matching lines @@
 }
 
 // Comparison, so that |Handle|s can be used as keys in hash maps.
 inline bool operator==(const Handle a, const Handle b) {
   return a.value() == b.value();
 }
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_SYSTEM_HANDLE_H_