Cache Storage: Add Platform API to retrieve CacheStorage for origin

public/platform/Platform.h

Index: public/platform/Platform.h
diff --git a/public/platform/Platform.h b/public/platform/Platform.h
index 6f50d496c3e41f01c650a76c141327faa9991f22..f9cf64a37e36676fd3826e0fc7472c3419e3853c 100644
--- a/public/platform/Platform.h
+++ b/public/platform/Platform.h
@@ -73,7 +73,6 @@ class WebCookieJar;
 class WebCrypto;
 class WebDatabaseObserver;
 class WebDiscardableMemory;
-class WebPlatformEventListener;
 class WebFallbackThemeEngine;
 class WebFileSystem;
 class WebFileUtilities;
@@ -91,6 +90,7 @@ class WebMimeRegistry;
 class WebNavigatorConnectProvider;
 class WebNotificationManager;
 class WebPermissionClient;
+class WebPlatformEventListener;
 class WebPluginListBuilder;
 class WebPrescientNetworking;
 class WebPublicSuffixList;
@@ -99,8 +99,9 @@ class WebRTCPeerConnectionHandler;
 class WebRTCPeerConnectionHandlerClient;
 class WebSandboxSupport;
 class WebScheduler;
-class WebSecurityOrigin;
 class WebScrollbarBehavior;
+class WebSecurityOrigin;
+class WebServiceWorkerCacheStorage;
 class WebSocketHandle;
 class WebSpeechSynthesizer;
 class WebSpeechSynthesizerClient;
@@ -219,6 +220,11 @@ public:
     virtual WebIDBFactory* idbFactory() { return 0; }
 
 
+    // Cache Storage ----------------------------------------------------------
+
+    // The caller is responsible for deleting the returned object.
+    virtual WebServiceWorkerCacheStorage* cacheStorage(const WebString& identifier) { return nullptr; }

[michaeln, 2015/03/25 00:12:35]

Maybe 'originIdentifier' for clarity. Also, should we say 0 or nullptr? Just
checking since i see lots of 0s in this file.

[kinuko, 2015/03/25 03:57:23]

I think nullptr is fine/preferred in new code.

[jsbell, 2015/03/25 16:25:52]

originIdentifier - Done. I left it as nullptr, though.

+
     // Gamepad -------------------------------------------------------------
 
     virtual void sampleGamepads(WebGamepads& into) { into.length = 0; }