Enable building pdf_use_skia in the standalone build.

skia/skia.gyp

+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+{
+  'conditions': [
+    # In component mode (shared_lib), we build all of skia as a single DLL.
+    # However, in the static mode, we need to build skia as multiple targets
+    # in order to support the use case where a platform (e.g. Android) may
+    # already have a copy of skia as a system library.
+    ['component=="static_library"', {
+      'targets': [
+        {
+          'target_name': 'skia_library',
+          'type': 'static_library',
+          # The optimize: 'max' scattered throughout are particularly
+          # important when compiled by MSVC 2013, which seems
+          # to mis-link-time-compile code that's built with
+          # different optimization levels. http://crbug.com/543583
+          'variables': {
+            'optimize': 'max',
+          },
+          'includes': [
+            'skia_common.gypi',
+            'skia_library.gypi',
+          ],
+        },
+      ],
+    }],
+    ['component=="static_library"', {
+      'targets': [
+        {
+          'target_name': 'skia',
+          # The optimize: 'max' scattered throughout are particularly
+          # important when compiled by MSVC 2013, which seems
+          # to mis-link-time-compile code that's built with
+          # different optimization levels. http://crbug.com/543583
+          'variables': {
+            'optimize': 'max',
+          },
+          'type': 'none',
+          'dependencies': [
+            'skia_library',
+            'skia_pdfium',
+          ],
+          'export_dependent_settings': [
+            'skia_library',
+            'skia_pdfium',
+          ],
+          'direct_dependent_settings': {
+            'conditions': [
+              [ 'OS == "win"', {
+                'defines': [
+                  'GR_GL_FUNCTION_TYPE=__stdcall',
+                ],
+              }],
+            ],
+          },
+        },
+        {
+          'target_name': 'skia_pdfium',
+          'type': 'static_library',
+          'includes': [
+            'skia_pdfium.gypi',
+            'skia_common.gypi',
+          ],
+        },
+      ],
+    }],
+  ],
+}