Reland^2: Use "gfxstream" namespace

This reverts commit 04c96274efbb8c845f7a4a8609f85fd4c6982ef3.

Reland adds in aosp/2516595 which was only built on the "full"
target and removes namespace around window methods to satisfy
MacOS build.

Bug: b/271464937
Test: android build
Test: cmake build
Change-Id: Iaf9c35e89938613e998110641a5112872e079c57
diff --git a/system/vulkan_enc/VulkanHandleMapping.h b/system/vulkan_enc/VulkanHandleMapping.h
index 5c03d7f..7c7fdbc 100644
--- a/system/vulkan_enc/VulkanHandleMapping.h
+++ b/system/vulkan_enc/VulkanHandleMapping.h
@@ -18,7 +18,8 @@
 
 #include "VulkanHandles.h"
 
-namespace goldfish_vk {
+namespace gfxstream {
+namespace vk {
 
 class VulkanHandleMapping {
 public:
@@ -45,4 +46,5 @@
     GOLDFISH_VK_LIST_HANDLE_TYPES(DECLARE_HANDLE_MAP_OVERRIDE)
 };
 
-} // namespace goldfish_vk
\ No newline at end of file
+}  // namespace vk
+}  // namespace gfxstream
\ No newline at end of file