Change transport dib API to not make copies of SharedMemoryHandle.

ui/surface/transport_dib_posix.cc

Index: ui/surface/transport_dib_posix.cc
diff --git a/ui/surface/transport_dib_posix.cc b/ui/surface/transport_dib_posix.cc
index e26fdb2d7c6e4a93c6932e071616ce5eae68f5a4..74957d2b845b230dd2df0372fb27fcb352cbe8c4 100644
--- a/ui/surface/transport_dib_posix.cc
+++ b/ui/surface/transport_dib_posix.cc
@@ -72,7 +72,7 @@ skia::PlatformCanvas* TransportDIB::GetPlatformCanvas(int w, int h) {
 }
 
 bool TransportDIB::Map() {
-  if (!is_valid_handle(handle()))
+  if (!is_valid_handle(shared_memory_.handle()))
     return false;
 #if defined(OS_ANDROID)
   if (!shared_memory_.Map(0))
@@ -98,12 +98,8 @@ void* TransportDIB::memory() const {
 
 TransportDIB::Id TransportDIB::id() const {
 #if defined(OS_ANDROID)
-  return handle();
+  return shared_memory_.handle();
 #else
   return shared_memory_.id();
 #endif
 }
-
-TransportDIB::Handle TransportDIB::handle() const {
-  return shared_memory_.handle();
-}