Implement OSGetCurrentProcessID

Change-Id: I96a964a9d5d4d8ac5b4bc3115a832a258c05bda2
diff --git a/BUILD.gn b/BUILD.gn
index c134d74..53e85ee 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -208,6 +208,7 @@
     "//garnet/lib/magma/src/magma_util/platform:barriers",
     "//garnet/lib/magma/src/magma_util/platform:buffer",
     "//garnet/lib/magma/src/magma_util/platform:device",
+    "//garnet/lib/magma/src/magma_util/platform:thread",
     "//zircon/public/lib/zx",
   ]
 }
diff --git a/services/server/env/fuchsia/osfunc.cc b/services/server/env/fuchsia/osfunc.cc
index 6e40c8b..e31f0e7 100644
--- a/services/server/env/fuchsia/osfunc.cc
+++ b/services/server/env/fuchsia/osfunc.cc
@@ -40,6 +40,7 @@
 #include "magma_util/macros.h"
 #include "platform_barriers.h"
 #include "platform_bus_mapper.h"
+#include "platform_thread.h"
 
 extern "C" {
 #include "allocmem.h"
@@ -380,8 +381,7 @@
 IMG_PID
 OSGetCurrentProcessID(void)
 {
-	NOT_IMPLEMENTED();
-	return 0;
+	return magma::PlatformProcessHelper::GetCurrentProcessId();
 }
 
 IMG_CHAR *