Move third_party/stb to flutter/third_party. (flutter/engine#48845)

As part of eliminating the Flutter buildroot (https://github.com/flutter/flutter/issues/67373), we are moving all third-party dependencies from `//third_party` to `//flutter/third_party`.

DEPS

@@ -715,7 +715,7 @@ deps = {
   'src/third_party/json':
   Var('flutter_git') + '/third_party/json.git' + '@' + '17d9eacd248f58b73f4d1be518ef649fe2295642',
 
-  'src/third_party/stb':
+  'src/flutter/third_party/stb':
   Var('flutter_git') + '/third_party/stb.git' + '@' + '5736b15f7ea0ffb08dd38af21067c314d6a3aae9',
 
   'src/third_party/gradle': {

engine/src/flutter/build/secondary/flutter/third_party/stb/BUILD.gn

@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source_root = "//third_party/stb"
+source_root = "//flutter/third_party/stb"
 
 source_set("stb_truetype") {
   testonly = true
@@ -11,5 +11,7 @@ source_set("stb_truetype") {
 
   include_dirs = [ "$source_root" ]
 
-  sources = [ "//flutter/build/secondary/third_party/stb/stb_truetype_stub.cc" ]
+  sources = [
+    "//flutter/build/secondary/flutter/third_party/stb/stb_truetype_stub.cc",
+  ]
 }

engine/src/flutter/build/secondary/flutter/third_party/stb/stb_truetype_stub.cc

@@ -3,4 +3,4 @@
 // found in the LICENSE file.
 
 #define STB_TRUETYPE_IMPLEMENTATION
-#include "third_party/stb/stb_truetype.h"
+#include "flutter/third_party/stb/stb_truetype.h"

engine/src/flutter/ci/licenses_golden/excluded_files

@@ -1043,6 +1043,7 @@
 ../../../flutter/third_party/sqlite/Makefile
 ../../../flutter/third_party/sqlite/README.md
 ../../../flutter/third_party/sqlite/VERSION
+../../../flutter/third_party/stb
 ../../../flutter/third_party/test_shaders
 ../../../flutter/third_party/tinygltf
 ../../../flutter/third_party/tonic/.clang-format
@@ -3020,7 +3021,6 @@
 ../../../third_party/root_certificates/certdata.pem
 ../../../third_party/root_certificates/certdata.txt
 ../../../third_party/root_certificates/codereview.settings
-../../../third_party/stb
 ../../../third_party/swiftshader
 ../../../third_party/vulkan-deps/.git
 ../../../third_party/vulkan-deps/.gitattributes

engine/src/flutter/ci/licenses_golden/tool_signature

@@ -1,2 +1,2 @@
-Signature: 5dbd06463802f22fb8c461c9bda734b8
+Signature: 8063c36f273a2ca0d4db5f05f9d5991a
 

engine/src/flutter/impeller/typographer/backends/stb/BUILD.gn

@@ -20,6 +20,6 @@ impeller_component("typographer_stb_backend") {
 
   public_deps = [
     "//flutter/impeller/typographer",
-    "//third_party/stb:stb_truetype",
+    "//flutter/third_party/stb:stb_truetype",
   ]
 }

engine/src/flutter/impeller/typographer/backends/stb/typeface_stb.h

@@ -6,9 +6,9 @@
 
 #include "flutter/fml/macros.h"
 #include "flutter/fml/mapping.h"
+#include "flutter/third_party/stb/stb_truetype.h"
 #include "impeller/base/backend_cast.h"
 #include "impeller/typographer/typeface.h"
-#include "third_party/stb/stb_truetype.h"
 
 namespace impeller {
 

engine/src/flutter/tools/licenses/lib/paths.dart

@@ -90,6 +90,7 @@ final Set<String> skippedPaths = <String>{
   r'flutter/third_party/skia/third_party/lua', // not linked in
   r'flutter/third_party/skia/third_party/vello', // not linked in
   r'flutter/third_party/skia/tools', // contains nothing that ends up in the binary executable
+  r'flutter/third_party/stb',
   r'flutter/third_party/test_shaders', // for tests only
   r'flutter/third_party/tinygltf',
   r'flutter/third_party/txt/third_party/fonts',
@@ -183,7 +184,6 @@ final Set<String> skippedPaths = <String>{
   r'third_party/protobuf', // build-time dependency only
   r'third_party/root_certificates/certdata.pem',
   r'third_party/root_certificates/certdata.txt',
-  r'third_party/stb',
   r'third_party/swiftshader', // only used on hosts for tests
   r'third_party/vulkan-deps/glslang/LICENSE', // excluded to make sure we don't accidentally apply it as a default license
   r'third_party/vulkan-deps/glslang/src/LICENSE.txt', // redundant with licenses inside files