Handle |public| in check_gn_headers.py

If |public| of a target contains files, count them as recognized
headers as well.

BUG=661774

Review-Url: https://codereview.chromium.org/2841323003
Cr-Commit-Position: refs/heads/master@{#467826}

build/check_gn_headers.py

@@ -76,7 +76,12 @@ def ParseGNProjectJSON(gn):
   all_headers = set()
 
   for _target, properties in gn['targets'].iteritems():
-    for f in properties.get('sources', []):
+    sources = properties.get('sources', [])
+    public = properties.get('public', [])
+    # Exclude '"public": "*"'.
+    if type(public) is list:
+      sources += public
+    for f in sources:
       if f.endswith('.h') or f.endswith('.hh'):
         if f.startswith('//'):
           f = f[2:]  # Strip the '//' prefix.

build/check_gn_headers_unittest.py

@@ -38,8 +38,14 @@ gn_input = json.loads(r'''
       "//:All": {
       },
       "//:base": {
+         "public": [ "//base/p.h" ],
          "sources": [ "//base/a.cc", "//base/a.h", "//base/b.hh" ],
          "visibility": [ "*" ]
+      },
+      "//:star_public": {
+         "public": "*",
+         "sources": [ "//base/c.h" ],
+         "visibility": [ "*" ]
       }
     }
 }
@@ -88,6 +94,8 @@ class CheckGnHeadersTest(unittest.TestCase):
     expected = set([
         'base/a.h',
         'base/b.hh',
+        'base/c.h',
+        'base/p.h',
     ])
     self.assertEquals(headers, expected)