Add skia extension to allow setting default fontmgr on linux. Use it to allow the linux blimp clien…

skia/BUILD.gn

Index: skia/BUILD.gn
diff --git a/skia/BUILD.gn b/skia/BUILD.gn
index e74662610d45975e6f6aa6b0fadf7186271bb99a..44ae7853b176c0928a37069af845a3552cf4e309 100644
--- a/skia/BUILD.gn
+++ b/skia/BUILD.gn
@@ -209,6 +209,7 @@ component("skia") {
     "ext/benchmarking_canvas.cc",
     "ext/convolver.cc",
     "ext/event_tracer_impl.cc",
+    "ext/fontmgr_default_linux.cc",
     "ext/fontmgr_default_win.cc",
     "ext/google_logging.cc",
     "ext/image_operations.cc",
@@ -251,7 +252,6 @@ component("skia") {
     "//third_party/skia/src/ports/SkFontHost_mac.cpp",
     "//third_party/skia/src/ports/SkFontHost_win.cpp",
     "//third_party/skia/src/ports/SkFontMgr_FontConfigInterface.cpp",
-    "//third_party/skia/src/ports/SkFontMgr_FontConfigInterface_factory.cpp",
     "//third_party/skia/src/ports/SkFontMgr_android.cpp",
     "//third_party/skia/src/ports/SkFontMgr_android_factory.cpp",
     "//third_party/skia/src/ports/SkFontMgr_android_parser.cpp",
@@ -368,7 +368,6 @@ component("skia") {
       "//third_party/skia/src/ports/SkFontConfigInterface_direct.cpp",
       "//third_party/skia/src/ports/SkFontConfigInterface_direct_factory.cpp",
       "//third_party/skia/src/ports/SkFontMgr_FontConfigInterface.cpp",
-      "//third_party/skia/src/ports/SkFontMgr_FontConfigInterface_factory.cpp",
     ]
   }