Make PopupMenuTest run on all platforms.

Source/web/web.gypi

 {
   'variables': {
     'web_files': [
       'ApplicationCacheHost.cpp',
       'ApplicationCacheHostInternal.h',
       'AssertMatchingEnums.cpp',
       'AssociatedURLLoader.cpp',
       'AssociatedURLLoader.h',
       'BackForwardClientImpl.cpp',
       'BackForwardClientImpl.h',
@@ skipping 282 matching lines @@
       'tests/KeyboardTest.cpp',
       'tests/LinkHighlightTest.cpp',
       'tests/ListenerLeakTest.cpp',
       'tests/MemoryInfo.cpp',
       'tests/MockWebGraphicsContext3D.h',
       'tests/OpaqueRectTrackingContentLayerDelegateTest.cpp',
       'tests/OpenTypeVerticalDataTest.cpp',
       'tests/PageSerializerTest.cpp',
       'tests/PaintAggregatorTest.cpp',
       'tests/PopupContainerTest.cpp',
+      'tests/PopupMenuTest.cpp',
       'tests/PrerenderingTest.cpp',
       'tests/ProgrammaticScrollTest.cpp',
       'tests/RenderTableCellTest.cpp',
       'tests/RenderTableRowTest.cpp',
       'tests/ScrollingCoordinatorChromiumTest.cpp',
       'tests/SpinLockTest.cpp',
       'tests/TouchActionTest.cpp',
       'tests/URLTestHelpers.cpp',
       'tests/URLTestHelpers.h',
       'tests/ViewportTest.cpp',
@@ skipping 11 matching lines @@
       'tests/WebURLRequestTest.cpp',
       'tests/WebURLResponseTest.cpp',
       'tests/WebUserGestureTokenTest.cpp',
       'tests/WebViewTest.cpp',
     ],
     'conditions': [
       ['OS=="win"',
         {
           'web_unittest_files': [
             'tests/LocaleWinTest.cpp',
-            # FIXME: Port PopupMenuTest to Linux and Mac.
-            'tests/PopupMenuTest.cpp',
             'tests/TransparencyWinTest.cpp',
             'tests/WebPageNewSerializerTest.cpp',
             'tests/WebPageSerializerTest.cpp',
           ],
         }
       ],
       ['OS=="win" and "ENABLE_HARFBUZZ_ON_WINDOWS=0" in feature_defines',
         {
           'web_unittest_files': [
             'tests/UniscribeHelperTest.cpp',
@@ skipping 26 matching lines @@
         {
           'web_unittest_files': [
             'tests/KeyCodeConversionTestGtk.cpp',
             'tests/WebInputEventFactoryTestGtk.cpp',
           ],
         }
       ],
     ],
   },
 }