clean-up and clarify CreatePlatformCanvas methods

ui/surface/transport_dib_posix.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 <stddef.h>
 #include <stdint.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ skipping 45 matching lines @@
 // static
 bool TransportDIB::is_valid_handle(Handle dib) {
   return base::SharedMemory::IsHandleValid(dib);
 }
 
 std::unique_ptr<SkCanvas> TransportDIB::GetPlatformCanvas(int w,
                                                           int h,
                                                           bool opaque) {
   if ((!memory() && !Map()) || !VerifyCanvasSize(w, h))
     return NULL;
-  return skia::CreatePlatformCanvas(w, h, opaque,
-                                    reinterpret_cast<uint8_t*>(memory()),
-                                    skia::RETURN_NULL_ON_FAILURE);
+  return skia::CreatePlatformCanvasWithPixels(
+      w, h, opaque, reinterpret_cast<uint8_t*>(memory()),
+      skia::RETURN_NULL_ON_FAILURE);
 }
 
 bool TransportDIB::Map() {
   if (!is_valid_handle(shared_memory_.handle()))
     return false;
 #if defined(OS_ANDROID)
   if (!shared_memory_.Map(0))
     return false;
   size_ = shared_memory_.mapped_size();
 #else
   if (memory())
     return true;
 
   size_t size;
   bool success = base::SharedMemory::GetSizeFromSharedMemoryHandle(
       shared_memory_.handle(), &size);
   if (!success || !shared_memory_.Map(size))
     return false;
 
   size_ = size;
 #endif
   return true;
 }
 
 void* TransportDIB::memory() const {
   return shared_memory_.memory();
 }