Make shared memory allocation possible for all child process types.

content/common/child_thread.cc

Index: content/common/child_thread.cc
===================================================================
--- content/common/child_thread.cc	(revision 105562)
+++ content/common/child_thread.cc	(working copy)
@@ -125,6 +125,39 @@
   return resource_dispatcher()->CreateBridge(request_info);
 }
 
+base::SharedMemory* ChildThread::AllocateSharedMemory(
+    size_t buf_size) {
+  scoped_ptr<base::SharedMemory> shared_buf;
+#if defined(OS_WIN)
+  shared_buf.reset(new base::SharedMemory);
+  if (!shared_buf->CreateAndMapAnonymous(buf_size)) {
+    NOTREACHED();
+    return NULL;
+  }
+#else
+  // On POSIX, we need to ask the browser to create the shared memory for us,
+  // since this is blocked by the sandbox.
+  base::SharedMemoryHandle shared_mem_handle;
+  if (Send(new ChildProcessHostMsg_SyncAllocateSharedMemory(
+                   buf_size, &shared_mem_handle))) {
+    if (base::SharedMemory::IsHandleValid(shared_mem_handle)) {
+      shared_buf.reset(new base::SharedMemory(shared_mem_handle, false));
+      if (!shared_buf->Map(buf_size)) {
+        NOTREACHED() << "Map failed";
+        return NULL;
+      }
+    } else {
+      NOTREACHED() << "Browser failed to allocate shared memory";
+      return NULL;
+    }
+  } else {
+    NOTREACHED() << "Browser allocation request message failed";
+    return NULL;
+  }
+#endif
+  return shared_buf.release();
+}
+
 ResourceDispatcher* ChildThread::resource_dispatcher() {
   return resource_dispatcher_.get();
 }