memory coordinator: Throttle background renderers on Android

content/browser/memory/memory_coordinator_unittest.cc

 // Copyright 2016 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_coordinator.h"
 
 #include "base/memory/memory_pressure_monitor.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace content {
 
 namespace {
 
 void RunUntilIdle() {
   base::RunLoop loop;
   loop.RunUntilIdle();
 }
 
 }  // namespace
 
 // A mock ChildMemoryCoordinator, for testing interaction between MC and CMC.
 class MockChildMemoryCoordinator : public mojom::ChildMemoryCoordinator {
  public:
   MockChildMemoryCoordinator()
-      : state_(mojom::MemoryState::UNKNOWN),
+      : state_(mojom::MemoryState::NORMAL),

[bashi, 2016/12/09 03:11:16]

I had to change the initial state to NORMAL because MemoryCoordinator::ChildInfo
is initialized with NORMAL state. SetChildMemoryState() won't call
OnStateChange() when a given state and the current state are the same. It means
that the first call of SetChildMemoryState(NORMAL) doesn't change |state_| and
it remains UNKNOWN, resulted in unexpected behavior.

         on_state_change_calls_(0) {}
 
   ~MockChildMemoryCoordinator() override {}
 
   void OnStateChange(mojom::MemoryState state) override {
     state_ = state;
     ++on_state_change_calls_;
   }
 
   mojom::MemoryState state() const { return state_; }
@@ skipping 91 matching lines @@
   EXPECT_EQ(1, cmc1->on_state_change_calls());
   EXPECT_EQ(mojom::MemoryState::THROTTLED, cmc1->state());
 
   EXPECT_TRUE(mc.SetChildMemoryState(2, mojom::MemoryState::SUSPENDED));
   EXPECT_EQ(1, cmc2->on_state_change_calls());
   // Child processes are considered as visible (foreground) by default,
   // and visible ones won't be suspended but throttled.
   EXPECT_EQ(mojom::MemoryState::THROTTLED, cmc2->state());
 }
 
+TEST_F(MemoryCoordinatorTest, SetChildMemoryState) {
+  TestMemoryCoordinator mc;
+  auto cmc = mc.CreateChildMemoryCoordinator(1);
+  auto iter = mc.children().find(1);
+  ASSERT_TRUE(iter != mc.children().end());
+
+  // Foreground
+  iter->second.is_visible = true;
+  EXPECT_TRUE(mc.SetChildMemoryState(1, mojom::MemoryState::NORMAL));
+  EXPECT_EQ(mojom::MemoryState::NORMAL, cmc->state());
+  EXPECT_TRUE(mc.SetChildMemoryState(1, mojom::MemoryState::THROTTLED));
+  EXPECT_EQ(mojom::MemoryState::THROTTLED, cmc->state());
+  EXPECT_TRUE(mc.SetChildMemoryState(1, mojom::MemoryState::SUSPENDED));
+  EXPECT_EQ(mojom::MemoryState::THROTTLED, cmc->state());
+
+  // Background
+  iter->second.is_visible = false;
+  EXPECT_TRUE(mc.SetChildMemoryState(1, mojom::MemoryState::NORMAL));
+#if defined(OS_ANDROID)
+  EXPECT_EQ(mojom::MemoryState::THROTTLED, cmc->state());
+#else
+  EXPECT_EQ(mojom::MemoryState::NORMAL, cmc->state());
+#endif
+  EXPECT_TRUE(mc.SetChildMemoryState(1, mojom::MemoryState::THROTTLED));
+  EXPECT_EQ(mojom::MemoryState::THROTTLED, cmc->state());
+  EXPECT_TRUE(mc.SetChildMemoryState(1, mojom::MemoryState::SUSPENDED));
+  EXPECT_EQ(mojom::MemoryState::SUSPENDED, cmc->state());
+}
+
 }  // namespace content