Replace web_cache_messages.h with Mojo service.

components/web_cache.gypi

Index: components/web_cache.gypi
diff --git a/components/web_cache.gypi b/components/web_cache.gypi
index 53b0714d638e773b04a20b2540e5427ae2c9ef30..957772116601d69e47343869e06f94f2d3649ff8 100644
--- a/components/web_cache.gypi
+++ b/components/web_cache.gypi
@@ -5,16 +5,16 @@
 {
   'targets': [
     {
+      # GN version: //components/web_cache/common
       'target_name': 'web_cache_common',

[Ken Rockot(use gerrit already), 2016/02/18 03:45:06]

I think we should rename this to web_cache_mojo_bindings or web_cache_mojom or
something.

[leonhsl(Using Gerrit), 2016/02/18 08:56:22]

Renamed to web_cache_mojo_bindings.

       'type': 'static_library',
-      'dependencies': [
-        '<(DEPTH)/ipc/ipc.gyp:ipc',
-      ],
-      'sources': [
-        'web_cache/common/web_cache_message_generator.cc',
-        'web_cache/common/web_cache_message_generator.h',
-        'web_cache/common/web_cache_messages.h',
-      ],
+      'variables': {
+        'mojom_files': [
+          # NOTE: Sources duplicated in //components/web_cache/common/BUILD.gn
+          'web_cache/common/web_cache_service.mojom',
+        ],
+      },
+      'includes': [ '../mojo/mojom_bindings_generator.gypi'],

[Ken Rockot(use gerrit already), 2016/02/18 03:45:06]

For mojom_bindings_generator.gypi you just use 'sources', rather than
'variables.mojom_files'. The latter is only for
mojom_bindings_generator_explicit.gypi, but its use is discouraged now.

[leonhsl(Using Gerrit), 2016/02/18 08:56:22]

Understood and Done.

     },
     {
       'target_name': 'web_cache_browser',