Architecture for cross-process memory notification suppressing

content/browser/memory/memory_message_filter.cc

Index: content/browser/memory/memory_message_filter.cc
diff --git a/content/browser/memory/memory_message_filter.cc b/content/browser/memory/memory_message_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..278e85392767c3183fbf7d3f525e9a2869b289ee
--- /dev/null
+++ b/content/browser/memory/memory_message_filter.cc
@@ -0,0 +1,79 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/memory/memory_message_filter.h"
+
+#include "base/bind.h"
+#include "base/memory/memory_pressure_listener.h"
+#include "content/common/memory_messages.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace content {
+namespace memory {
+
+MemoryMessageFilter::MemoryMessageFilter()
+    : BrowserMessageFilter(MemoryMsgStart) {}
+
+MemoryMessageFilter::~MemoryMessageFilter() {}
+
+void MemoryMessageFilter::OnFilterAdded(IPC::Sender* sender) {
+  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
+    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+                            base::Bind(&MemoryMessageFilter::OnFilterAdded,
+                                       base::Unretained(this), sender));
+    return;
+  }
+  memory_message_filters_.Get().insert(this);
+  if (base::MemoryPressureListener::AreNotificationsSuppressed())
+    SendSetNotificationsSuppressed(true);
+}
+
+void MemoryMessageFilter::OnFilterRemoved() {
+  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
+    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+                            base::Bind(&MemoryMessageFilter::OnFilterRemoved,
+                                       base::Unretained(this)));
+    return;
+  }
+  memory_message_filters_.Get().erase(this);
+}
+
+bool MemoryMessageFilter::OnMessageReceived(const IPC::Message& message) {
+  return false;
+}
+
+// static
+base::LazyInstance<MemoryMessageFilter::MemoryMessageFilterSet>::Leaky
+    MemoryMessageFilter::memory_message_filters_ = LAZY_INSTANCE_INITIALIZER;
+
+// static
+void MemoryMessageFilter::SendSetNotificationsSuppressedToAllProcesses(
+    bool suppressed) {
+  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        base::Bind(
+            &MemoryMessageFilter::SendSetNotificationsSuppressedToAllProcesses,
+            suppressed));
+    return;
+  }
+
+  // Enable/disable suppressing memory notifications in the browser process.
+  base::MemoryPressureListener::SetNotificationsSuppressed(suppressed);
+
+  // Enable/disable suppressing memory notifications in all child processes.
+  MemoryMessageFilterSet& filters = memory_message_filters_.Get();
+  for (MemoryMessageFilterSet::iterator it = filters.begin();
+       it != filters.end(); ++it) {
+    it->get()->SendSetNotificationsSuppressed(suppressed);
+  }
+}
+
+void MemoryMessageFilter::SendSetNotificationsSuppressed(bool suppressed) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  Send(new MemoryMsg_SetNotificationsSuppressed(suppressed));
+}
+
+}  // namespace memory
+}  // namespace content