[Sync] Add type conversion constructor for WeakHandle

chrome/browser/sync/util/weak_handle_unittest.cc

 // Copyright (c) 2011 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/browser/sync/util/weak_handle.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/location.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
 #include "base/threading/thread.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace browser_sync {
-namespace {
 
 using ::testing::_;
 using ::testing::SaveArg;
 using ::testing::StrictMock;
 
 class Base {
  public:
   Base() : weak_ptr_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {}
 
   WeakHandle<Base> AsWeakHandle() {
     return MakeWeakHandle(weak_ptr_factory_.GetWeakPtr());
   }
 
   void Kill() {
     weak_ptr_factory_.InvalidateWeakPtrs();
   }
 
   MOCK_METHOD0(Test, void());
   MOCK_METHOD1(Test1, void(const int&));
   MOCK_METHOD2(Test2, void(const int&, Base*));
   MOCK_METHOD3(Test3, void(const int&, Base*, float));
   MOCK_METHOD4(Test4, void(const int&, Base*, float, const char*));
 
   MOCK_METHOD1(TestWithSelf, void(const WeakHandle<Base>&));
 
  private:
   base::WeakPtrFactory<Base> weak_ptr_factory_;
 };
 
+class Derived : public Base, public base::SupportsWeakPtr<Derived> {};
+
 class WeakHandleTest : public ::testing::Test {
  protected:
   virtual void TearDown() {
     // Process any last-minute posted tasks.
     PumpLoop();
   }
 
   void PumpLoop() {
     message_loop_.RunAllPending();
   }
@@ skipping 196 matching lines @@
     h = b.AsWeakHandle();
     EXPECT_TRUE(h.IsInitialized());
     h.Call(FROM_HERE, &Base::Test);
     h.Reset();
     EXPECT_FALSE(h.IsInitialized());
   }
 
   PumpLoop();
 }
 
-}  // namespace
+TEST_F(WeakHandleTest, TypeConversionConstructor) {
+  StrictMock<Derived> d;
+  EXPECT_CALL(d, Test()).Times(2);
+
+  const WeakHandle<Derived> weak_handle = MakeWeakHandle(d.AsWeakPtr());
+
+  // Should trigger type conversion constructor.
+  const WeakHandle<Base> base_weak_handle(weak_handle);
+  // Should trigger regular copy constructor.
+  const WeakHandle<Derived> derived_weak_handle(weak_handle);
+
+  EXPECT_TRUE(base_weak_handle.IsInitialized());
+  base_weak_handle.Call(FROM_HERE, &Base::Test);
+
+  EXPECT_TRUE(derived_weak_handle.IsInitialized());
+  // Copy constructor shouldn't construct a new |core_|.
+  EXPECT_EQ(weak_handle.core_.get(), derived_weak_handle.core_.get());
+  derived_weak_handle.Call(FROM_HERE, &Base::Test);
+
+  PumpLoop();
+}
+
+TEST_F(WeakHandleTest, TypeConversionConstructorMakeWeakHandle) {
+  const base::WeakPtr<Derived> weak_ptr;
+
+  // Should trigger type conversion constructor after MakeWeakHandle.
+  WeakHandle<Base> base_weak_handle(MakeWeakHandle(weak_ptr));
+  // Should trigger regular copy constructor after MakeWeakHandle.
+  const WeakHandle<Derived> derived_weak_handle(MakeWeakHandle(weak_ptr));
+
+  EXPECT_TRUE(base_weak_handle.IsInitialized());
+  EXPECT_TRUE(derived_weak_handle.IsInitialized());
+}
+
+TEST_F(WeakHandleTest, TypeConversionConstructorAssignment) {
+  const WeakHandle<Derived> weak_handle =
+      MakeWeakHandle(Derived().AsWeakPtr());
+
+  // Should trigger type conversion constructor before the assignment.
+  WeakHandle<Base> base_weak_handle;
+  base_weak_handle = weak_handle;
+  // Should trigger regular copy constructor before the assignment.
+  WeakHandle<Derived> derived_weak_handle;
+  derived_weak_handle = weak_handle;
+
+  EXPECT_TRUE(base_weak_handle.IsInitialized());
+  EXPECT_TRUE(derived_weak_handle.IsInitialized());
+  // Copy constructor shouldn't construct a new |core_|.
+  EXPECT_EQ(weak_handle.core_.get(), derived_weak_handle.core_.get());
+}
+
+TEST_F(WeakHandleTest, TypeConversionConstructorUninitialized) {
+  const WeakHandle<Base> base_weak_handle = WeakHandle<Derived>();
+  EXPECT_FALSE(base_weak_handle.IsInitialized());
+}
+
+TEST_F(WeakHandleTest, TypeConversionConstructorUninitializedAssignment) {
+  WeakHandle<Base> base_weak_handle;
+  base_weak_handle = WeakHandle<Derived>();
+  EXPECT_FALSE(base_weak_handle.IsInitialized());
+}
+
 }  // namespace browser_sync