Simplify the transport dib situation across our various platforms, as a

ui/surface/transport_dib_mac.cc

-// Copyright (c) 2012 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.
-
-#include "ui/surface/transport_dib.h"
-
-#include <sys/stat.h>
-#include <unistd.h>
-
-#include "base/logging.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/memory/shared_memory.h"
-#include "base/posix/eintr_wrapper.h"
-#include "skia/ext/platform_canvas.h"
-
-TransportDIB::TransportDIB()
-    : size_(0) {
-}
-
-TransportDIB::TransportDIB(TransportDIB::Handle dib)
-    : shared_memory_(dib, false /* read write */),
-      size_(0) {
-}
-
-TransportDIB::~TransportDIB() {
-}
-
-// static
-TransportDIB* TransportDIB::Create(size_t size, uint32 sequence_num) {
-  TransportDIB* dib = new TransportDIB;
-  if (!dib->shared_memory_.CreateAndMapAnonymous(size)) {
-    delete dib;
-    return NULL;
-  }
-
-  dib->size_ = size;
-  return dib;
-}
-
-// static
-TransportDIB* TransportDIB::Map(Handle handle) {
-  scoped_ptr<TransportDIB> dib(CreateWithHandle(handle));
-  if (!dib->Map())
-    return NULL;
-  return dib.release();
-}
-
-// static
-TransportDIB* TransportDIB::CreateWithHandle(Handle handle) {
-  return new TransportDIB(handle);
-}
-
-// static
-bool TransportDIB::is_valid_handle(Handle dib) {
-  return dib.fd >= 0;
-}
-
-// static
-bool TransportDIB::is_valid_id(Id id) {
-  return id != 0;
-}
-
-skia::PlatformCanvas* TransportDIB::GetPlatformCanvas(int w, int h) {
-  if ((!memory() && !Map()) || !VerifyCanvasSize(w, h))
-    return NULL;
-  return skia::CreatePlatformCanvas(w, h, true, 
-                                    reinterpret_cast<uint8_t*>(memory()),
-                                    skia::RETURN_NULL_ON_FAILURE);
-}
-
-bool TransportDIB::Map() {
-  if (!is_valid_handle(handle()))
-    return false;
-  if (memory())
-    return true;
-
-  struct stat st;
-  if ((fstat(shared_memory_.handle().fd, &st) != 0) ||
-      (!shared_memory_.Map(st.st_size))) {
-    return false;
-  }
-
-  size_ = st.st_size;
-  return true;
-}
-
-void* TransportDIB::memory() const {
-  return shared_memory_.memory();
-}
-
-TransportDIB::Id TransportDIB::id() const {
-  return shared_memory_.id();
-}
-
-TransportDIB::Handle TransportDIB::handle() const {
-  return shared_memory_.handle();
-}