[Win] Create ModuleWatcher.

chrome/common/conflicts/module_watcher_win_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 "chrome/common/conflicts/module_watcher_win.h"
+
+#include "base/bind.h"
+#include "base/message_loop/message_loop.h"
+#include "base/observer_list_threadsafe.h"
+#include "base/run_loop.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace conflicts {
+
+class ModuleWatcherTest : public testing::Test {
+ public:
+  ModuleWatcherTest()
+      : module_(nullptr),
+        module_event_count_(0),
+        module_already_loaded_event_count_(0),
+        module_loaded_event_count_(0),
+        module_unloaded_event_count_(0) {}
+
+  void OnModuleEvent(const ModuleWatcher::ModuleEvent& event) {
+    module_event_count_++;
+    switch (event.event_type) {
+      case ModuleWatcher::MODULE_ALREADY_LOADED:
+        module_already_loaded_event_count_++;
+        break;
+      case ModuleWatcher::MODULE_LOADED:
+        module_loaded_event_count_++;
+        break;
+      case ModuleWatcher::MODULE_UNLOADED:
+        module_unloaded_event_count_++;
+        break;
+    }
+  }
+
+  void SetUp() override {
+    message_loop_.reset(new base::MessageLoopForUI());
+    observer_ = mw_.RegisterCallback(
+        base::Bind(&ModuleWatcherTest::OnModuleEvent, base::Unretained(this)));
+  }
+
+  void TearDown() override {
+    observer_.reset();
+    message_loop_.reset();
+    UnloadModule();
+  }
+
+  void RunLoopUntilIdle() { base::RunLoop().RunUntilIdle(); }
+
+  void AssertNoObservers() { mw_.observer_list_->AssertEmpty(); }
+
+  void LoadModule() {
+    if (module_)
+      return;
+    // This module should not be a static dependency of the unit-test
+    // executable, but should be a build-system dependency or a module that is
+    // present on any Windows machine.
+    static const wchar_t kModuleName[] = L"chrome.dll";
+    // The module should not already be loaded.
+    ASSERT_FALSE(::GetModuleHandle(kModuleName));
+    // It should have loaded successfully.
+    module_ = ::LoadLibrary(kModuleName);
+    ASSERT_TRUE(module_);
+  }
+
+  void UnloadModule() {
+    if (!module_)
+      return;
+    ::FreeLibrary(module_);
+    module_ = nullptr;
+  }
+
+  // The module watcher used by the test.
+  ModuleWatcher mw_;
+
+  // The observer object.
+  std::unique_ptr<ModuleWatcher::Observer> observer_;
+
+  // Holds a handle to a loaded module.
+  HMODULE module_;
+
+  // Total number of module events seen.
+  size_t module_event_count_;
+  // Total number of MODULE_ALREADY_LOADED events seen.
+  size_t module_already_loaded_event_count_;
+  // Total number of MODULE_LOADED events seen.
+  size_t module_loaded_event_count_;
+  // Total number of MODULE_UNLOADED events seen.
+  size_t module_unloaded_event_count_;
+
+ private:
+  std::unique_ptr<base::MessageLoopForUI> message_loop_;
+
+  DISALLOW_COPY_AND_ASSIGN(ModuleWatcherTest);
+};
+
+TEST_F(ModuleWatcherTest, ModuleEvents) {
+  EXPECT_FALSE(mw_.IsRunning());
+  EXPECT_EQ(0u, module_event_count_);
+
+  // Start the watcher and ensure it enumerates already loaded modules.
+  mw_.Start();
+  EXPECT_TRUE(mw_.IsRunning());
+  RunLoopUntilIdle();
+  EXPECT_LT(0u, module_event_count_);
+  EXPECT_LT(0u, module_already_loaded_event_count_);
+  EXPECT_EQ(0u, module_loaded_event_count_);
+  EXPECT_EQ(0u, module_unloaded_event_count_);
+
+  // Dynamically load a module and ensure it a notification is received for it.
+  LoadModule();
+  RunLoopUntilIdle();
+  EXPECT_EQ(1u, module_loaded_event_count_);
+
+  // Unload the module and ensure another notification is received.
+  UnloadModule();
+  RunLoopUntilIdle();
+  EXPECT_EQ(1u, module_unloaded_event_count_);
+
+  // Dynamically load a module and ensure it a notification is received for it.
+  LoadModule();
+  RunLoopUntilIdle();
+  EXPECT_EQ(2u, module_loaded_event_count_);
+
+  // Stop the module watcher.
+  mw_.Stop();
+
+  // Unload the module and ensure no notification is received this time.
+  UnloadModule();
+  RunLoopUntilIdle();
+  EXPECT_EQ(1u, module_unloaded_event_count_);
+
+  // Clean up the observer and ensure it was removed.
+  observer_.reset();
+  AssertNoObservers();
+}
+
+}  // namespace conflicts