Make shared memory allocation possible for all child process types.

content/common/child_process_messages.h

Index: content/common/child_process_messages.h
===================================================================
--- content/common/child_process_messages.h	(revision 104763)
+++ content/common/child_process_messages.h	(working copy)
@@ -5,6 +5,7 @@
 // Common IPC messages used for child processes.
 // Multiply-included message file, hence no include guard.
 
+#include "base/shared_memory.h"
 #include "content/common/content_export.h"
 #include "googleurl/src/gurl.h"
 #include "ipc/ipc_message_macros.h"
@@ -78,3 +79,9 @@
 // Release the cached font
 IPC_MESSAGE_CONTROL0(ChildProcessHostMsg_ReleaseCachedFonts)
 #endif  // defined(OS_WIN)
+
+// Asks the browser to create a block of shared memory for the child process to
+// fill in and pass back to the browser.
+IPC_SYNC_MESSAGE_CONTROL1_1(ChildProcessHostMsg_SyncAllocateSharedMemory,
+                            size_t /* buffer size */,

[jam, 2011/10/12 03:01:30]

this was a unit32 on purpose, since we want IPC messages to be able to move
between 32 and 64 bit processes, and size_t would be different size

+                            base::SharedMemoryHandle)