Simplify BrowserContext by removing redundant methods.

extensions/browser/content_hash_fetcher.cc

Index: extensions/browser/content_hash_fetcher.cc
diff --git a/extensions/browser/content_hash_fetcher.cc b/extensions/browser/content_hash_fetcher.cc
index dbe0f2185ab4cc03fd733d737ca0843b44ab6ffb..883f44ff94f619d7a5234a69411d7d9065f8e7d1 100644
--- a/extensions/browser/content_hash_fetcher.cc
+++ b/extensions/browser/content_hash_fetcher.cc
@@ -21,6 +21,7 @@
 #include "base/version.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/storage_partition.h"
 #include "crypto/sha2.h"
 #include "extensions/browser/computed_hashes.h"
 #include "extensions/browser/content_hash_tree.h"
@@ -462,7 +463,9 @@ void ContentHashFetcher::DoFetch(const Extension* extension, bool force) {
   GURL url =
       delegate_->GetSignatureFetchUrl(extension->id(), *extension->version());
   ContentHashFetcherJob* job = new ContentHashFetcherJob(
-      context_->GetRequestContext(), delegate_->GetPublicKey(), extension->id(),
+      content::BrowserContext::GetDefaultStoragePartition(context_)->
+          GetURLRequestContext(),
+      delegate_->GetPublicKey(), extension->id(),
       extension->path(), url, force,
       base::Bind(&ContentHashFetcher::JobFinished,
                  weak_ptr_factory_.GetWeakPtr()));