Migrate HostZoomMap to live in StoragePartition.

content/public/browser/host_zoom_map.h

Index: content/public/browser/host_zoom_map.h
diff --git a/content/public/browser/host_zoom_map.h b/content/public/browser/host_zoom_map.h
index e65b443d2b4a64590e3aca78ef3ba45c3a0873d5..f5a06b2e54b24d255690b388a3f41db03817fcb7 100644
--- a/content/public/browser/host_zoom_map.h
+++ b/content/public/browser/host_zoom_map.h
@@ -13,11 +13,13 @@
 #include "base/callback.h"
 #include "base/callback_list.h"
 #include "content/common/content_export.h"
+#include "url/gurl.h"
 
 namespace content {
 
 class BrowserContext;
 class ResourceContext;
+class SiteInstance;
 class WebContents;
 
 // Maps hostnames to custom zoom levels.  Written on the UI thread and read on
@@ -55,6 +57,11 @@ class HostZoomMap {
   CONTENT_EXPORT static HostZoomMap* GetForBrowserContext(
       BrowserContext* browser_context);
 
+  CONTENT_EXPORT static HostZoomMap* GetForSite(SiteInstance* instance);
+
+  CONTENT_EXPORT static HostZoomMap* GetForWebContents(
+      const WebContents* contents);
+
   // Returns the current zoom level for the specified WebContents. May be
   // temporary or host-specific.
   CONTENT_EXPORT static double GetZoomLevel(const WebContents* web_contents);