Enable GL interfaces for iOS build

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1703923002

Review URL: https://codereview.chromium.org/1703923002
diff --git a/public.bzl b/public.bzl
index 6239254..987d7c5 100644
--- a/public.bzl
+++ b/public.bzl
@@ -97,6 +97,7 @@
         "src/doc/SkDocument_PDF_None.cpp",  # We use SkDocument_PDF.cpp.
         "src/gpu/gl/GrGLCreateNativeInterface_none.cpp",
         "src/gpu/gl/GrGLDefaultInterface_native.cpp",
+        "src/gpu/gl/GrGLDefaultInterface_none.cpp",
 
         # Exclude files that don't compile with the current DEFINES.
         "src/gpu/gl/angle/*",  # Requires SK_ANGLE define.
@@ -122,6 +123,7 @@
         "src/android/*",
         "src/codec/*",
         "src/fonts/SkFontMgr_fontconfig.cpp",
+        "src/gpu/gl/GrGLDefaultInterface_none.cpp",
         "src/images/*",
         "src/opts/**/*.cpp",
         "src/opts/**/*.h",
@@ -169,6 +171,7 @@
     include = [
         "src/android/*",
         "src/codec/*",
+        "src/gpu/gl/GrGLDefaultInterface_none.cpp",
         "src/images/*",
         # TODO(benjaminwagner): Figure out how to compile with EGL.
         "src/opts/**/*.cpp",
@@ -212,6 +215,8 @@
 # Platform-dependent SRCS for google3-default iOS.
 BASE_SRCS_IOS = struct(
     include = [
+        "src/gpu/gl/GrGLDefaultInterface_native.cpp",
+        "src/gpu/gl/iOS/GrGLCreateNativeInterface_iOS.cpp",
         "src/opts/**/*.cpp",
         "src/opts/**/*.h",
         "src/ports/**/*.cpp",