Replace web_cache_messages.h with Mojo service.

components/web_cache/browser/web_cache_manager.h

Index: components/web_cache/browser/web_cache_manager.h
diff --git a/components/web_cache/browser/web_cache_manager.h b/components/web_cache/browser/web_cache_manager.h
index a0c19073612c326778bc3109dfc636a823581ad5..cc781519e0d10e048d097ba6ff19ee402847f3aa 100644
--- a/components/web_cache/browser/web_cache_manager.h
+++ b/components/web_cache/browser/web_cache_manager.h
@@ -19,6 +19,7 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
+#include "components/web_cache/public/interfaces/web_cache.mojom.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
@@ -140,6 +141,9 @@ class WebCacheManager : public content::NotificationObserver {
   // each renderer is permitted to consume for its cache.
   typedef std::list<Allocation> AllocationStrategy;
 
+  // The key is the unique id of every render process host.
+  typedef std::map<int, mojom::WebCachePtr> WebCacheServicesMap;
+
   // This class is a singleton.  Do not instantiate directly.
   WebCacheManager();
   friend struct base::DefaultSingletonTraits<WebCacheManager>;
@@ -257,6 +261,9 @@ class WebCacheManager : public content::NotificationObserver {
 
   content::NotificationRegistrar registrar_;
 
+  // Maps every renderer_id with its corresponding mojom::WebCachePtr.
+  WebCacheServicesMap web_cache_services_;
+
   base::WeakPtrFactory<WebCacheManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebCacheManager);