[Extensions] Make ProcessManager::GetSiteInstanceForUrl return ref ptr

ProcessManager::GetSiteInstanceForUrl calls through into
SiteInstance::GetRelatedSiteInstance(), which has the appropriate comment
"Callers should ensure that this SiteInstance becomes ref counted, by storing
it in a scoped_refptr." This implies that GetSiteInstanceForUrl should return
a refptr (as, probably, should GetRelatedSiteInstance, but that's a bigger
change).

(Discovered by a test failing on asan for leaking a site instance.)

BUG=456858
TBR=mtomasz@chromium.org (micro file manager change)

Review URL: https://codereview.chromium.org/890603005

Cr-Commit-Position: refs/heads/master@{#315457}

1 files changed, 2 insertions, 5 deletions

diff --git a/extensions/browser/process_manager.h b/extensions/browser/process_manager.h
index 2bfcb60e4..60056a1 100644
--- a/extensions/browser/process_manager.h
+++ b/extensions/browser/process_manager.h
@@ -73,13 +73,10 @@ class ProcessManager : public KeyedService,
   ExtensionHost* GetBackgroundHostForExtension(const std::string& extension_id);
 
   // Returns the SiteInstance that the given URL belongs to.
-  // Callers should wrap the result in a scoped_refptr to ensure the
-  // SiteInstance becomes refcounted.
-  // TODO(devlin): The above comment clearly indicates that this should just
-  // return a refptr. Update callers.
   // TODO(aa): This only returns correct results for extensions and packaged
   // apps, not hosted apps.
-  virtual content::SiteInstance* GetSiteInstanceForURL(const GURL& url);
+  virtual scoped_refptr<content::SiteInstance> GetSiteInstanceForURL(
+      const GURL& url);
 
   // If the view isn't keeping the lazy background page alive, increments the
   // keepalive count to do so.