Use SDKROOT in the paths to OSX framework to match Chromium

BUG=angleproject:891

Change-Id: I458a12bd6b4be3b262d76184c51bde1f2b803c67
Reviewed-on: https://chromium-review.googlesource.com/299730
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tryjob-Request: Corentin Wallez <cwallez@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>

build/common_defines.gypi

@@ -21,6 +21,9 @@
                 'angle_use_glx%': 0,
             }],
         ],
+
+        # root of the OSX SDK for Chromium builds, the system root for standalone builds
+        'SDKROOT%': "",
     },
     'msvs_disabled_warnings':
     [

src/libGLESv2.gypi

@@ -744,14 +744,12 @@
                             ],
                             'link_settings':
                             {
-                                # TODO(cwallez) Chromium uses an SDKROOT prefix, use it when we want to
-                                # support compiling ANGLE in Chromium on Mac
                                 'libraries':
                                 [
-                                    'OpenGL.framework',
-                                    'IOSurface.framework',
-                                    'Cocoa.framework',
-                                    'QuartzCore.framework',
+                                    '$(SDKROOT)/System/Library/Frameworks/OpenGL.framework',
+                                    '$(SDKROOT)/System/Library/Frameworks/IOSurface.framework',
+                                    '$(SDKROOT)/System/Library/Frameworks/Cocoa.framework',
+                                    '$(SDKROOT)/System/Library/Frameworks/QuartzCore.framework',
                                 ],
                             },
                             'all_dependent_settings':

util/util.gyp

@@ -145,12 +145,10 @@
                     ],
                     'link_settings':
                     {
-                        # TODO(cwallez) Chromium uses an SDKROOT prefix, use it when we want to
-                        # support compiling ANGLE in Chromium on Mac
                         'libraries':
                         [
-                            'AppKit.framework',
-                            'QuartzCore.framework',
+                            '$(SDKROOT)/System/Library/Frameworks/AppKit.framework',
+                            '$(SDKROOT)/System/Library/Frameworks/QuartzCore.framework',
                         ],
                     },
                 }],