[GN] Define SK_BUILD_NO_OPTS when building skia on iOS.

skia/skia_common.gypi

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This gypi file handles the removal of platform-specific files from the
 # Skia build.
 {
   'includes': [
     # chromium_skia_defines.gypi defines chromium_skia_defines
     'chromium_skia_defines.gypi',
@@ skipping 13 matching lines @@
          ['exclude', '_android\\.(cc|cpp)$'],
       ],
     }],
     [ 'OS != "ios"', {
       'sources/': [
          ['exclude', '_ios\\.(cc|cpp|mm?)$'],
       ],
     }],
     [ 'OS == "ios"', {
       'defines': [
+        # When targetting iOS and using gyp to generate the build files, it is
+        # not possible to select files to build depending on the architecture
+        # (i.e. it is not possible to use hand optimized assembly version). In
+        # that configuration, disable all optimisation.
         'SK_BUILD_FOR_IOS',
+        'SK_BUILD_NO_OPTS',
       ],
     }],
     [ 'OS != "mac"', {
       'sources/': [
         ['exclude', '_mac\\.(cc|cpp|mm?)$'],
       ],
     }],
     [ 'OS == "mac"', {
       'defines': [
         'SK_BUILD_FOR_MAC',
@@ skipping 127 matching lines @@
   # re-export if they include Skia headers in their public headers.
   'all_dependent_settings': {
     'include_dirs': [
       '..',
       'config',
     ],
   },
 
   'msvs_disabled_warnings': [4244, 4267, 4341, 4345, 4390, 4554, 4748, 4800],
 }