[Blob] BlobReader class & tests, and removal of all redundant reading.

content/browser/fileapi/blob_url_request_job_unittest.cc

Index: content/browser/fileapi/blob_url_request_job_unittest.cc
diff --git a/content/browser/fileapi/blob_url_request_job_unittest.cc b/content/browser/fileapi/blob_url_request_job_unittest.cc
index 9debd4dc6715caf70b602336f2a6d713a3734665..f4708df506d0a9d338001f2048e1102683de5622 100644
--- a/content/browser/fileapi/blob_url_request_job_unittest.cc
+++ b/content/browser/fileapi/blob_url_request_job_unittest.cc
@@ -115,7 +115,7 @@ class BlobURLRequestJobTest : public testing::Test {
         net::URLRequest* request,
         net::NetworkDelegate* network_delegate) const override {
       return new BlobURLRequestJob(request, network_delegate,
-                                   test_->GetSnapshotFromBuilder(),
+                                   test_->GetHandleFromBuilder(),
                                    test_->file_system_context_.get(),
                                    base::ThreadTaskRunnerHandle::Get().get());
     }
@@ -282,18 +282,19 @@ class BlobURLRequestJobTest : public testing::Test {
     *expected_result += std::string(kTestFileSystemFileData2 + 6, 7);
   }
 
-  scoped_ptr<BlobDataSnapshot> GetSnapshotFromBuilder() {
+  storage::BlobDataHandle* GetHandleFromBuilder() {
     if (!blob_handle_) {
       blob_handle_ = blob_context_.AddFinishedBlob(blob_data_.get()).Pass();
     }
-    return blob_handle_->CreateSnapshot().Pass();
+    return blob_handle_.get();
   }
 
   // This only works if all the Blob items have a definite pre-computed length.
   // Otherwise, this will fail a CHECK.
   int64 GetTotalBlobLength() {
     int64 total = 0;
-    scoped_ptr<BlobDataSnapshot> data = GetSnapshotFromBuilder();
+    scoped_ptr<BlobDataSnapshot> data =
+        GetHandleFromBuilder()->CreateSnapshot();
     const auto& items = data->items();
     for (const auto& item : items) {
       int64 length = base::checked_cast<int64>(item->length());