Require gn format in presubmit

BUILD.gn

 # Copyright 2016 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 declare_args() {
 }
 
 skia_public_includes = [
   "include/android",
@@ skipping 346 matching lines @@
     "tools/gpu/gl/debug/GrProgramObj.cpp",
     "tools/gpu/gl/debug/GrShaderObj.cpp",
     "tools/gpu/gl/debug/GrTextureObj.cpp",
     "tools/gpu/gl/debug/GrTextureUnitObj.cpp",
     "tools/gpu/gl/null/NullGLTestContext.cpp",
   ]
   libs = []
 
   if (is_linux) {
     sources += [
-        "src/gpu/gl/glx/GrGLCreateNativeInterface_glx.cpp",
-        "tools/gpu/gl/glx/CreatePlatformGLTestContext_glx.cpp",
+      "src/gpu/gl/glx/GrGLCreateNativeInterface_glx.cpp",
+      "tools/gpu/gl/glx/CreatePlatformGLTestContext_glx.cpp",
     ]
     libs += [
       "GL",
       "GLU",
       "X11",
     ]
   } else if (is_mac) {
     sources += [
-        "src/gpu/gl/mac/GrGLCreateNativeInterface_mac.cpp",
-        "tools/gpu/gl/mac/CreatePlatformGLTestContext_mac.cpp",
+      "src/gpu/gl/mac/GrGLCreateNativeInterface_mac.cpp",
+      "tools/gpu/gl/mac/CreatePlatformGLTestContext_mac.cpp",
     ]
     libs += [ "OpenGL.framework" ]
   }
 }
 
 test_lib("flags") {
   public_include_dirs = [ "tools/flags" ]
   sources = [
     "tools/flags/SkCommandLineFlags.cpp",
     "tools/flags/SkCommonFlags.cpp",
@@ skipping 62 matching lines @@
                             ],
                             "list lines",
                             [])
 
 test_lib("tests") {
   public_include_dirs = [ "tests" ]
   sources = tests_sources - [
               rebase_path("tests/FontMgrAndroidParserTest.cpp"),  # Android only
               rebase_path("tests/PathOpsSkpClipTest.cpp"),  # alternate main
               rebase_path("tests/RTConfRegistryTest.cpp"),  # TODO: delete
-              rebase_path("tests/SkSLErrorTest.cpp"),   # TODO: make work
-              rebase_path("tests/SkSLGLSLTest.cpp"),   # TODO: make work
+              rebase_path("tests/SkSLErrorTest.cpp"),  # TODO: make work
+              rebase_path("tests/SkSLGLSLTest.cpp"),  # TODO: make work
               rebase_path("tests/SkpSkGrTest.cpp"),  # doesn't compile
               rebase_path("tests/skia_test.cpp"),  # alternate main
             ]
   deps = [
     ":flags",
     ":gpu_tool_utils",
     ":skia",
     ":tool_utils",
     "//third_party/libpng",
     "//third_party/zlib",
@@ skipping 65 matching lines @@
       ":flags",
       ":gm",
       ":gpu_tool_utils",
       ":skia",
       ":tool_utils",
       "//third_party/jsoncpp",
     ]
     testonly = true
   }
 }