Revert of Reland #1 "ipc: Add a new field num_brokered_attachments to the message header." (patchset #4 id:60001 of https://codereview.chromium.org/1330563002/ )

Reason for revert:
This CL was only ever intended to make it into one Canary.

Original issue's description:
> Reland #1 "ipc: Add a new field num_brokered_attachments to the message header."
>
> This otherwise innocuous CL is causing an unusual crash in Canary. At first
> glance, the crash appears related to IPC, but further digging indicates that
> it's probably related to corruption of a ResourceBuffer. I've updated that class
> to use CHECKs instead of DCHECKs https://codereview.chromium.org/1325153002/.
>
> I expect this CL to cause ~100 crashes in the next Chrome Canary. I intend to
> revert this CL after a single Canary release. This CL will help me better
> diagnose the exact nature of the crash.
>
> BUG=493414
>
> Committed: https://crrev.com/d32c32bef61d80f68208e550ace18f50f1c498d1
> Cr-Commit-Position: refs/heads/master@{#347250}

TBR=tsepez@chromium.org,avi@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=493414

Review URL: https://codereview.chromium.org/1314803005

Cr-Commit-Position: refs/heads/master@{#347429}

2 files changed, 0 insertions, 19 deletions

diff --git a/ipc/ipc_message.cc b/ipc/ipc_message.cc
index e9e1dcb..07d5d25 100644
--- a/ipc/ipc_message.cc
+++ b/ipc/ipc_message.cc
@@ -46,9 +46,6 @@ Message::~Message() {
 Message::Message() : base::Pickle(sizeof(Header)) {
   header()->routing = header()->type = 0;
   header()->flags = GetRefNumUpper24();
-#if USE_ATTACHMENT_BROKER
-  header()->num_brokered_attachments = 0;
-#endif
 #if defined(OS_POSIX)
   header()->num_fds = 0;
   header()->pad = 0;
@@ -62,9 +59,6 @@ Message::Message(int32 routing_id, uint32 type, PriorityValue priority)
   header()->type = type;
   DCHECK((priority & 0xffffff00) == 0);
   header()->flags = priority | GetRefNumUpper24();
-#if USE_ATTACHMENT_BROKER
-  header()->num_brokered_attachments = 0;
-#endif
 #if defined(OS_POSIX)
   header()->num_fds = 0;
   header()->pad = 0;
@@ -137,12 +131,6 @@ bool Message::WriteAttachment(scoped_refptr<MessageAttachment> attachment) {
   // We write the index of the descriptor so that we don't have to
   // keep the current descriptor as extra decoding state when deserialising.
   WriteInt(attachment_set()->size());
-
-#if USE_ATTACHMENT_BROKER
-  if (attachment->GetType() == MessageAttachment::TYPE_BROKERABLE_ATTACHMENT)
-    header()->num_brokered_attachments += 1;
-#endif
-
   return attachment_set()->AddAttachment(attachment);
 }
 
diff --git a/ipc/ipc_message.h b/ipc/ipc_message.h
index d0e38af..d12f6a3 100644
--- a/ipc/ipc_message.h
+++ b/ipc/ipc_message.h
@@ -11,7 +11,6 @@
 #include "base/memory/ref_counted.h"
 #include "base/pickle.h"
 #include "base/trace_event/trace_event.h"
-#include "ipc/attachment_broker.h"
 #include "ipc/ipc_export.h"
 
 #if !defined(NDEBUG)
@@ -223,12 +222,6 @@ class IPC_EXPORT Message : public base::Pickle {
     int32 routing;  // ID of the view that this message is destined for
     uint32 type;    // specifies the user-defined message type
     uint32 flags;   // specifies control flags for the message
-#if USE_ATTACHMENT_BROKER
-    // The number of brokered attachments included with this message. The
-    // ids of the brokered attachment ids are sent immediately after the pickled
-    // message, before the next pickled message is sent.
-    uint32 num_brokered_attachments;
-#endif
 #if defined(OS_POSIX)
     uint16 num_fds; // the number of descriptors included with this message
     uint16 pad;     // explicitly initialize this to appease valgrind