<chromium> Make linking against ANGLE libraries optional

Change-Id: I004dc2a75f9ab27939f65cb784b56ca1ef86db28
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>

chromium/content/content_gpu.gypi

@@ -40,7 +40,7 @@
         ],
       },
     }],
-    ['qt_os=="win32"', {
+    ['qt_os=="win32" and qt_gl=="angle"', {
       'link_settings': {
         'libraries': [
           '-lsetupapi.lib',

chromium/ui/compositor/compositor.gyp

@@ -75,7 +75,7 @@
             '<(angle_path)/src/build_angle.gyp:libGLESv2',
           ],
         }],
-        ['use_aura == 1 and qt_os=="win32"', {
+        ['use_aura == 1 and qt_os=="win32" and qt_gl=="angle"', {
           'libraries': [
             '-l<(qt_egl_library)',
             '-l<(qt_glesv2_library)',