Replace web_cache_messages.h with Mojo service.

components/web_cache/common/web_cache_service.mojom

Index: components/web_cache/common/web_cache_service.mojom
diff --git a/components/web_cache/common/web_cache_service.mojom b/components/web_cache/common/web_cache_service.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..520e8405e275229c3f22f3fed85f76cfedcfb327
--- /dev/null
+++ b/components/web_cache/common/web_cache_service.mojom
@@ -0,0 +1,16 @@
+// Copyright 2016 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.
+
+module web_cache;

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

Please always use a mojom suffix for module names, i.e. web_cache.mojom.

This way generated bindings will consistently live in a mojom sub-namespace and
avoid collision with non-mojom types.

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

Understood and done.

+
+interface WebCacheService {
+  // Set cache capacity values.
+  // Each call is independent, overlapping calls are possible.
+  SetCacheCapacities(uint64 min_dead_capacity,
+                     uint64 max_dead_capacity,
+                     uint64 capacity);
+  // Clear cache.
+  // Each call is independent, overlapping calls are possible.
+  ClearCache(bool on_navigation);
+};