[Blob] Dependencies for blob storage testing

public/platform/WebBlobData.h

Index: public/platform/WebBlobData.h
diff --git a/public/platform/WebBlobData.h b/public/platform/WebBlobData.h
index fd92dffcf33d603322079a7615972e068a625ab8..98136cef8284e85619fa57cbbd614c717a8a0e66 100644
--- a/public/platform/WebBlobData.h
+++ b/public/platform/WebBlobData.h
@@ -68,6 +68,10 @@ public:
 
     // Retrieves the values of the item at the given index. Returns false if
     // index is out of bounds.
+    // This call is single use only per index. The memory ownership is
+    // transfered to the result in the case of memory items. A second call with
+    // the same index will result in null data.
+    // TODO(dmurph): change the name to 'takeItemAt'
     BLINK_PLATFORM_EXPORT bool itemAt(size_t index, Item& result) const;
 
     BLINK_PLATFORM_EXPORT WebString contentType() const;