Add architecture for simulating memory pressure notifications in all processes

content/browser/memory/memory_pressure_controller.cc

 // 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_pressure_controller.h"
 
 #include "base/bind.h"
-#include "base/memory/memory_pressure_listener.h"
 #include "content/browser/memory/memory_message_filter.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace content {
 
 MemoryPressureController::MemoryPressureController() {}
 
 MemoryPressureController::~MemoryPressureController() {}
 
 void MemoryPressureController::OnMemoryMessageFilterAdded(
@@ skipping 44 matching lines @@
   // Enable/disable suppressing memory notifications in the browser process.
   base::MemoryPressureListener::SetNotificationsSuppressed(suppressed);
 
   // Enable/disable suppressing memory notifications in all child processes.
   for (MemoryMessageFilterSet::iterator it = memory_message_filters_.begin();
        it != memory_message_filters_.end(); ++it) {
     it->get()->SendSetPressureNotificationsSuppressed(suppressed);
   }
 }
 
+void MemoryPressureController::SimulatePressureNotificationInAllProcesses(
+    MemoryPressureLevel level) {
+  DCHECK_NE(level, MemoryPressureLevel::MEMORY_PRESSURE_LEVEL_NONE);
+
+  if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
+    // Note that passing base::Unretained(this) is safe here because the
+    // controller is a leaky singleton (i.e. it is never deleted).

[Primiano Tucci (use gerrit), 2015/09/28 12:47:31]

the i.e. part in  parenthesis is really superfluos.

[petrcermak, 2015/09/28 15:39:32]

Done (removed in both methods).

+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE,
+        base::Bind(&MemoryPressureController::
+                       SimulatePressureNotificationInAllProcesses,
+                   base::Unretained(this), level));
+    return;
+  }
+
+  // Simulate memory pressure notification in the browser process.
+  base::MemoryPressureListener::SimulatePressureNotification(level);
+
+  // Simulate memory pressure notification in all child processes.
+  for (MemoryMessageFilterSet::iterator it = memory_message_filters_.begin();

[Primiano Tucci (use gerrit), 2015/09/28 12:47:31]

you could use a one-line C++11 style foreach here
for (scoped_refptr<MemoryMessageFilter>& mf : memory_message_filters_)

(the & ref avoids to temporary copy the scoped_refptr in the scope of the for)

[petrcermak, 2015/09/28 15:39:32]

Done (in both methods).

+       it != memory_message_filters_.end(); ++it) {
+    it->get()->SendSimulatePressureNotification(level);

[Primiano Tucci (use gerrit), 2015/09/28 12:47:32]

..and that will avoid you to use the ->get()
What an awesome saving of bytes :)

[petrcermak, 2015/09/28 15:39:32]

Done.

+  }
+}
+
 }  // namespace content