First pass on intents options UI.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 8d507ccab48e302fcd745a6818112bf1d7184070..9953bac3db9832ceb480a19e2dc6692bdfd35412 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -316,6 +316,7 @@
     'asan%': '<(asan)',
     'enable_register_protocol_handler%': '<(enable_register_protocol_handler)',
     'enable_smooth_scrolling%': '<(enable_smooth_scrolling)',
+    'enable_web_intents%': '<(enable_web_intents)',
     # Whether to build for Wayland display server
     'use_wayland%': 0,
 
@@ -706,6 +707,10 @@
         'grit_defines': ['-D', 'enable_register_protocol_handler'],
       }],
 
+      ['enable_web_intents==1', {
+        'grit_defines': ['-D', 'enable_web_intents'],
+      }],
+
       ['asan==1', {
         'clang%': 1,
       }],
@@ -922,6 +927,11 @@
           'ENABLE_REGISTER_PROTOCOL_HANDLER=1',
         ],
       }],
+      ['enable_web_intents==1', {
+        'defines': [
+          'ENABLE_INTENTS=1',
+        ],
+      }],
     ],  # conditions for 'target_defaults'
     'target_conditions': [
       ['chromium_code==0', {