Add architecture for simulating memory pressure notifications in all processes

content/browser/memory/memory_pressure_controller_browsertest.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 "base/bind.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "content/browser/memory/memory_message_filter.h"
 #include "content/browser/memory/memory_pressure_controller.h"
 #include "content/common/memory_messages.h"
 #include "content/public/test/content_browser_test.h"
 #include "content/public/test/content_browser_test_utils.h"
 #include "content/public/test/test_utils.h"
 #include "ipc/ipc_message.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace content {
 
+const auto MEMORY_PRESSURE_LEVEL_MODERATE =

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

you could move these two lines in the test that needs them

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

Done.

+    MemoryPressureLevel::MEMORY_PRESSURE_LEVEL_MODERATE;
+const auto MEMORY_PRESSURE_LEVEL_CRITICAL =
+    MemoryPressureLevel::MEMORY_PRESSURE_LEVEL_CRITICAL;
+
 MATCHER_P(IsSetSuppressedMessage, suppressed, "") {
   // Ensure that the message is deleted upon return.
   scoped_ptr<IPC::Message> message(arg);
   if (message == nullptr)
     return false;
   MemoryMsg_SetPressureNotificationsSuppressed::Param param;
   if (!MemoryMsg_SetPressureNotificationsSuppressed::Read(message.get(),
                                                           &param))
     return false;
   return suppressed == base::get<0>(param);
 }
 
+MATCHER_P(IsSimulateMessage, level, "") {
+  // Ensure that the message is deleted upon return.
+  scoped_ptr<IPC::Message> message(arg);
+  if (message == nullptr)
+    return false;
+  MemoryMsg_SimulatePressureNotification::Param param;
+  if (!MemoryMsg_SimulatePressureNotification::Read(message.get(), &param))
+    return false;
+  return level == base::get<0>(param);
+}
+
 class MemoryMessageFilterForTesting : public MemoryMessageFilter {
  public:
   MOCK_METHOD1(Send, bool(IPC::Message* message));
 
   void Add() {
     // The filter must be added on the IO thread.
     if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
       BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
                               base::Bind(&MemoryMessageFilterForTesting::Add,
                                          base::Unretained(this)));
@@ skipping 15 matching lines @@
     }
     OnChannelClosing();
     OnFilterRemoved();
   }
 
  protected:
   ~MemoryMessageFilterForTesting() override {}
 };
 
 class MemoryPressureControllerBrowserTest : public ContentBrowserTest {
+ public:
+  MOCK_METHOD1(OnMemoryPressure, void(MemoryPressureLevel level));
+
  protected:
   void SetPressureNotificationsSuppressedInAllProcessesAndWait(
       bool suppressed) {
     MemoryPressureController::GetInstance()
         ->SetPressureNotificationsSuppressedInAllProcesses(suppressed);
     RunAllPendingInMessageLoop(BrowserThread::IO);
   }
+
+  void SimulatePressureNotificationInAllProcessesAndWait(
+      MemoryPressureLevel level) {
+    MemoryPressureController::GetInstance()
+        ->SimulatePressureNotificationInAllProcesses(level);
+    RunAllPendingInMessageLoop(BrowserThread::IO);
+  }
 };
 
 IN_PROC_BROWSER_TEST_F(MemoryPressureControllerBrowserTest,
                        SetPressureNotificationsSuppressedInAllProcesses) {
   scoped_refptr<MemoryMessageFilterForTesting> filter1(
       new MemoryMessageFilterForTesting);
   scoped_refptr<MemoryMessageFilterForTesting> filter2(
       new MemoryMessageFilterForTesting);
 
   NavigateToURL(shell(), GetTestUrl("", "title.html"));
@@ skipping 39 matching lines @@
 
   // Remove the second filter and disable suppressing memory pressure
   // notifications in all processes. No messages should be sent.
   EXPECT_CALL(*filter1, Send(testing::_)).Times(0);
   EXPECT_CALL(*filter2, Send(testing::_)).Times(0);
   filter2->Remove();
   SetPressureNotificationsSuppressedInAllProcessesAndWait(false);
   EXPECT_FALSE(base::MemoryPressureListener::AreNotificationsSuppressed());
 }
 
+IN_PROC_BROWSER_TEST_F(MemoryPressureControllerBrowserTest,
+                       SimulatePressureNotificationInAllProcesses) {
+  scoped_refptr<MemoryMessageFilterForTesting> filter(
+      new MemoryMessageFilterForTesting);
+  scoped_ptr<base::MemoryPressureListener> listener(
+      new base::MemoryPressureListener(
+          base::Bind(&MemoryPressureControllerBrowserTest::OnMemoryPressure,
+                     base::Unretained(this))));
+
+  NavigateToURL(shell(), GetTestUrl("", "title.html"));
+
+  filter->Add();
+
+  EXPECT_CALL(*filter, Send(IsSimulateMessage(MEMORY_PRESSURE_LEVEL_CRITICAL)))
+      .Times(1);
+  EXPECT_CALL(*this, OnMemoryPressure(MEMORY_PRESSURE_LEVEL_CRITICAL)).Times(1);
+  SimulatePressureNotificationInAllProcessesAndWait(
+      MEMORY_PRESSURE_LEVEL_CRITICAL);
+  RunAllPendingInMessageLoop();  // Force the listener to run.

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

I'd reword the coomment to  "Wait for the listener"
This is not really "forcing" 

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

Done.

+
+  // Enable suppressing memory pressure notifications in all processes. This
+  // should have no impact on simulating memory pressure notifications.
+  EXPECT_CALL(*filter, Send(IsSetSuppressedMessage(true))).Times(1);
+  SetPressureNotificationsSuppressedInAllProcessesAndWait(true);
+
+  EXPECT_CALL(*filter, Send(IsSimulateMessage(MEMORY_PRESSURE_LEVEL_MODERATE)))
+      .Times(1);
+  EXPECT_CALL(*this, OnMemoryPressure(MEMORY_PRESSURE_LEVEL_MODERATE)).Times(1);
+  SimulatePressureNotificationInAllProcessesAndWait(
+      MEMORY_PRESSURE_LEVEL_MODERATE);
+  RunAllPendingInMessageLoop();  // Force the listener to run.
+
+  // Disable suppressing memory pressure notifications in all processes. This
+  // should have no impact on simulating memory pressure notifications.
+  EXPECT_CALL(*filter, Send(IsSetSuppressedMessage(false))).Times(1);
+  SetPressureNotificationsSuppressedInAllProcessesAndWait(false);
+
+  EXPECT_CALL(*filter, Send(IsSimulateMessage(MEMORY_PRESSURE_LEVEL_MODERATE)))
+      .Times(1);
+  EXPECT_CALL(*this, OnMemoryPressure(MEMORY_PRESSURE_LEVEL_MODERATE)).Times(1);
+  SimulatePressureNotificationInAllProcessesAndWait(
+      MEMORY_PRESSURE_LEVEL_MODERATE);
+  RunAllPendingInMessageLoop();  // Force the listener to run.
+
+  filter->Remove();
+}
+
 }  // namespace content