Expat target exports includes instead of FreeType.

Currently when building for Android framework the freetype target
exports the expat include directory, but the freetype target neither
uses nor logically provides this information. Instead, the expat target
itself should do this.

Review-Url: https://codereview.chromium.org/2283903003

gyp/android_deps.gyp

@@ -37,6 +37,9 @@
               'libraries' : [
                 '-lexpat',
               ],
+              'include_dirs': [
+                'external/expat/lib',
+              ],
             },
           },
           {

gyp/freetype.gyp

@@ -63,7 +63,6 @@
                     ],
                   },
                   'include_dirs': [
-                    'external/expat/lib',
                     'external/freetype/include',
                   ],
                   'libraries': [