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

content/browser/loader/upload_data_stream_builder.cc

Index: content/browser/loader/upload_data_stream_builder.cc
diff --git a/content/browser/loader/upload_data_stream_builder.cc b/content/browser/loader/upload_data_stream_builder.cc
index 12b4b80c9cf06bb5c2a0a22cf0eaff2dd6978a43..cab3a104572e3811b5c85d948c299b94b5bf33fb 100644
--- a/content/browser/loader/upload_data_stream_builder.cc
+++ b/content/browser/loader/upload_data_stream_builder.cc
@@ -4,7 +4,6 @@
 
 #include "content/browser/loader/upload_data_stream_builder.h"
 
-#include <limits>
 #include <utility>
 #include <vector>
 
@@ -14,11 +13,11 @@
 #include "content/common/resource_request_body.h"
 #include "net/base/elements_upload_data_stream.h"
 #include "net/base/upload_bytes_element_reader.h"
+#include "net/base/upload_disk_cache_entry_element_reader.h"
 #include "net/base/upload_file_element_reader.h"
 #include "storage/browser/blob/blob_data_handle.h"
-#include "storage/browser/blob/blob_reader.h"
+#include "storage/browser/blob/blob_data_snapshot.h"
 #include "storage/browser/blob/blob_storage_context.h"
-#include "storage/browser/blob/upload_blob_element_reader.h"
 
 namespace disk_cache {
 class Entry;
@@ -70,15 +69,89 @@
   DISALLOW_COPY_AND_ASSIGN(FileElementReader);
 };
 
+// This owns the provided ResourceRequestBody. This is necessary to ensure the
+// BlobData and open disk cache entries survive until upload completion.
+class DiskCacheElementReader : public net::UploadDiskCacheEntryElementReader {
+ public:
+  DiskCacheElementReader(ResourceRequestBody* resource_request_body,
+                         disk_cache::Entry* disk_cache_entry,
+                         int disk_cache_stream_index,
+                         const ResourceRequestBody::Element& element)
+      : net::UploadDiskCacheEntryElementReader(disk_cache_entry,
+                                               disk_cache_stream_index,
+                                               element.offset(),
+                                               element.length()),
+        resource_request_body_(resource_request_body) {
+    DCHECK_EQ(ResourceRequestBody::Element::TYPE_DISK_CACHE_ENTRY,
+              element.type());
+  }
+
+  ~DiskCacheElementReader() override {}
+
+ private:
+  scoped_refptr<ResourceRequestBody> resource_request_body_;
+
+  DISALLOW_COPY_AND_ASSIGN(DiskCacheElementReader);
+};
+
+void ResolveBlobReference(
+    ResourceRequestBody* body,
+    storage::BlobStorageContext* blob_context,
+    const ResourceRequestBody::Element& element,
+    std::vector<std::pair<const ResourceRequestBody::Element*,
+                          const storage::BlobDataItem*>>* resolved_elements) {
+  DCHECK(blob_context);
+  scoped_ptr<storage::BlobDataHandle> handle =
+      blob_context->GetBlobDataFromUUID(element.blob_uuid());
+  DCHECK(handle);
+  if (!handle)
+    return;
+
+  // TODO(dmurph): Create a reader for blobs instead of decomposing the blob
+  // and storing the snapshot on the request to keep the resources around.
+  // Currently a handle is attached to the request in the resource dispatcher
+  // host, so we know the blob won't go away, but it's not very clear or useful.
+  scoped_ptr<storage::BlobDataSnapshot> snapshot = handle->CreateSnapshot();
+  // If there is no element in the referred blob data, just return.
+  if (snapshot->items().empty())
+    return;
+
+  // Append the elements in the referenced blob data.
+  for (const auto& item : snapshot->items()) {
+    DCHECK_NE(storage::DataElement::TYPE_BLOB, item->type());
+    resolved_elements->push_back(
+        std::make_pair(item->data_element_ptr(), item.get()));
+  }
+  const void* key = snapshot.get();
+  body->SetUserData(key, snapshot.release());
+}
+
 }  // namespace
 
 scoped_ptr<net::UploadDataStream> UploadDataStreamBuilder::Build(
     ResourceRequestBody* body,
     storage::BlobStorageContext* blob_context,
     storage::FileSystemContext* file_system_context,
-    base::SingleThreadTaskRunner* file_task_runner) {
+    base::TaskRunner* file_task_runner) {
+  // Resolve all blob elements.
+  std::vector<std::pair<const ResourceRequestBody::Element*,
+                        const storage::BlobDataItem*>> resolved_elements;
+  for (size_t i = 0; i < body->elements()->size(); ++i) {
+    const ResourceRequestBody::Element& element = (*body->elements())[i];
+    if (element.type() == ResourceRequestBody::Element::TYPE_BLOB) {
+      ResolveBlobReference(body, blob_context, element, &resolved_elements);
+    } else if (element.type() !=
+               ResourceRequestBody::Element::TYPE_DISK_CACHE_ENTRY) {
+      resolved_elements.push_back(std::make_pair(&element, nullptr));
+    } else {
+      NOTREACHED();
+    }
+  }
+
   ScopedVector<net::UploadElementReader> element_readers;
-  for (const auto& element : *body->elements()) {
+  for (const auto& element_and_blob_item_pair : resolved_elements) {
+    const ResourceRequestBody::Element& element =
+        *element_and_blob_item_pair.first;
     switch (element.type()) {
       case ResourceRequestBody::Element::TYPE_BYTES:
         element_readers.push_back(new BytesElementReader(body, element));
@@ -99,18 +172,22 @@
                 element.length(),
                 element.expected_modification_time()));
         break;
-      case ResourceRequestBody::Element::TYPE_BLOB: {
-        DCHECK_EQ(std::numeric_limits<uint64_t>::max(), element.length());
-        DCHECK_EQ(0ul, element.offset());
-        scoped_ptr<storage::BlobDataHandle> handle =
-            blob_context->GetBlobDataFromUUID(element.blob_uuid());
-        storage::BlobDataHandle* handle_ptr = handle.get();
-        element_readers.push_back(new storage::UploadBlobElementReader(
-            handle_ptr->CreateReader(file_system_context, file_task_runner),
-            handle.Pass()));
+      case ResourceRequestBody::Element::TYPE_BLOB:
+        // Blob elements should be resolved beforehand.
+        // TODO(dmurph): Create blob reader and store the snapshot in there.
+        NOTREACHED();
+        break;
+      case ResourceRequestBody::Element::TYPE_DISK_CACHE_ENTRY: {
+        // TODO(gavinp): If Build() is called with a DataElement of
+        // TYPE_DISK_CACHE_ENTRY then this code won't work because we won't call
+        // ResolveBlobReference() and so we won't find |item|. Is this OK?
+        const storage::BlobDataItem* item = element_and_blob_item_pair.second;
+        element_readers.push_back(
+            new DiskCacheElementReader(body, item->disk_cache_entry(),
+                                       item->disk_cache_stream_index(),
+                                       element));
         break;
       }
-      case ResourceRequestBody::Element::TYPE_DISK_CACHE_ENTRY:
       case ResourceRequestBody::Element::TYPE_UNKNOWN:
         NOTREACHED();
         break;