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

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"
 
+// Desktop GTK Linux builds use the old-style SYSV SHM based DIBs.
+// Linux Aura and Chrome OS do too. This will change very soon.
+#if !defined(TOOLKIT_GTK) && !(defined(OS_LINUX) && defined(USE_AURA))
+
 #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()
@@ skipping 33 matching lines @@
   return new TransportDIB(handle);
 }
 
 // static
 bool TransportDIB::is_valid_handle(Handle dib) {
   return dib.fd >= 0;
 }
 
 // static
 bool TransportDIB::is_valid_id(Id id) {
+#if defined(OS_ANDROID)
+  return is_valid_handle(id);
+#else
   return id != 0;
+#endif
 }
 
 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 defined(OS_ANDROID)
+  if (!shared_memory_.Map(0))
+    return false;
+  size_ = shared_memory_.mapped_size();
+#else
   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;
+#endif
   return true;
 }
 
 void* TransportDIB::memory() const {
   return shared_memory_.memory();
 }
 
 TransportDIB::Id TransportDIB::id() const {
+#if defined(OS_ANDROID)
+  return handle();
+#else
   return shared_memory_.id();
+#endif
 }
 
 TransportDIB::Handle TransportDIB::handle() const {
   return shared_memory_.handle();
 }
+
+#endif  // !defined(TOOLKIT_GTK) && !(defined(OS_LINUX) && defined(USE_AURA))
+