Use ByteStream in downloads system to decouple source and sink.

tools/valgrind/memcheck/suppressions.txt

Index: tools/valgrind/memcheck/suppressions.txt
diff --git a/tools/valgrind/memcheck/suppressions.txt b/tools/valgrind/memcheck/suppressions.txt
index 32be2a6641c778210e2a097ac331305af527d80c..45a7bf5a9a60891389f06b4f739d67a8f27cd844 100644
--- a/tools/valgrind/memcheck/suppressions.txt
+++ b/tools/valgrind/memcheck/suppressions.txt
@@ -3498,22 +3498,6 @@
    fun:_ZN*DownloadManagerTest_*
 }
 {
-   bug_93006c
-   Memcheck:Leak
-   fun:_Znw*
-   fun:_ZN23DownloadResourceHandler10OnWillReadEiPPN3net8IOBufferEPii
-   fun:_ZN23BufferedResourceHandler27UseAlternateResourceHandlerEiP15ResourceHandler
-   fun:_ZN23BufferedResourceHandler23CompleteResponseStartedEib
-   fun:_ZN23BufferedResourceHandler15OnReadCompletedEiPi
-   fun:_ZN22ResourceDispatcherHost12CompleteReadEPN3net10URLRequestEPi
-   fun:_ZN22ResourceDispatcherHost15OnReadCompletedEPN3net10URLRequestEi
-   fun:_ZN3net10URLRequest19NotifyReadCompletedEi
-   fun:_ZN3net13URLRequestJob18NotifyReadCompleteEi
-   fun:_ZN3net17URLRequestTestJob20ProcessNextOperationEv
-   fun:_ZN3net17URLRequestTestJob24ProcessOnePendingMessageEv
-   fun:_ZN56ResourceDispatcherHostTest_*8TestBodyEv
-}
-{
    bug_93250a
    Memcheck:Leak
    fun:_Znw*
@@ -4846,23 +4830,6 @@
    fun:_ZN7WebCore17ClipboardChromium6createENS_9Clipboard13ClipboardTypeEN3WTF10PassRefPtrINS_18ChromiumDataObjectEEENS_21ClipboardAccessPolicyEPNS_5FrameE
 }
 {
-   bug_111588
-   Memcheck:Leak
-   fun:_Znw*
-   fun:_ZN23DownloadResourceHandler17OnResponseStartedEiPN7content16ResourceResponseE
-   fun:_ZN7content23BufferedResourceHandler33ForwardPendingEventsToNextHandlerEi
-   fun:_ZN7content23BufferedResourceHandler27UseAlternateResourceHandlerEiP15ResourceHandler
-   fun:_ZN7content23BufferedResourceHandler23CompleteResponseStartedEi
-   fun:_ZN7content23BufferedResourceHandler15OnReadCompletedEiPi
-   fun:_ZN22ResourceDispatcherHost12CompleteReadEPN3net10URLRequestEPi
-   fun:_ZN22ResourceDispatcherHost15OnReadCompletedEPN3net10URLRequestEi
-   fun:_ZN3net10URLRequest19NotifyReadCompletedEi
-   fun:_ZN3net13URLRequestJob18NotifyReadCompleteEi
-   fun:_ZN3net17URLRequestTestJob20ProcessNextOperationEv
-   fun:_ZN3net17URLRequestTestJob24ProcessOnePendingMessageEv
-   fun:_ZN56ResourceDispatcherHostTest_*_Test8TestBodyEv
-}
-{
    bug_111669
    Memcheck:Leak
    fun:_Znw*