Skia GN build.

This Cl makes GN execute correctly for builds with pdf_use_skia=true enabled.

BUG=pdfium:487

Review-Url: https://codereview.chromium.org/1932683003
diff --git a/DEPS b/DEPS
index 0368c39..146b6eb 100644
--- a/DEPS
+++ b/DEPS
@@ -4,18 +4,18 @@
   'chromium_git': 'https://chromium.googlesource.com',
   'pdfium_git': 'https://pdfium.googlesource.com',
 
-  'build_revision': '28e8fda8744c8c44bac72eee610642798daf2705',
-  'buildtools_revision': '5378d73123b64907773cc5c1bb027b2f765ff00a',
+  'build_revision': 'c557a3544d31513394681f40c8c2512cf7ddcb9e',
+  'buildtools_revision': '309289315767f615256eada4653b4917cf148c8e',
   'clang_revision': 'b6f620b311665e2d96d0921833f54295b9bbf925',
   'cygwin_revision': 'c89e446b273697fadf3a10ff1007a97c0b7de6df',
+  'gen_library_loader_revision': '916d4acd8b2cde67a390737dfba90b3c37de23a1',
   'gmock_revision': '29763965ab52f24565299976b936d1265cb6a271',
   'gtest_revision': '8245545b6dc9c4703e6496d1efd19e975ad2b038',
   'icu_revision': 'c291cde264469b20ca969ce8832088acb21e0c48',
   'pdfium_tests_revision': '7e5050a49256a7350df9b8d7ad86e911eb83c021',
-  'skia_revision': '0a291c7b7eea1807bd58bdaa60c258fd0ebeb257',
+  'skia_revision': '6f47dbaff54a7705ef3e98f1f65c765e56fd9bd0',
   'trace_event_revision': 'd83d44b13d07c2fd0a40101a7deef9b93b841732',
   'v8_revision': '5cd0d8f27e3f740179a8a3de7b9d2c0cfae7afb9',
-
 }
 
 deps = {
@@ -43,6 +43,10 @@
   "tools/clang":
     Var('chromium_git') + "/chromium/src/tools/clang@" +  Var('clang_revision'),
 
+  "tools/generate_library_loader":
+    Var('chromium_git') + "/chromium/src/tools/generate_library_loader@" +
+        Var('gen_library_loader_revision'),
+
   "tools/gyp":
     Var('chromium_git') + "/external/gyp",