Add ability to reorder custom links

Add functionality for reordering custom links. Will initialize if
custom links has not been initialized yet.

Bug: 851335
Change-Id: I67710b4187f8f5a45d7f96814c17294f87d60b22
Reviewed-on: https://chromium-review.googlesource.com/c/1308899
Commit-Queue: Kristi Park <kristipark@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#604419}

components/ntp_tiles/custom_links_manager.h

@@ -69,6 +69,11 @@ class CustomLinksManager {
   virtual bool UpdateLink(const GURL& url,
                           const GURL& new_url,
                           const base::string16& new_title) = 0;
+  // Moves the specified link from its current index and inserts it at
+  // |new_pos|. Returns false and does nothing if custom links is not
+  // initialized, |url| is invalid, |url| does not exist in the list, or
+  // |new_pos| is invalid/already the current index.
+  virtual bool ReorderLink(const GURL& url, size_t new_pos) = 0;
   // Deletes the link with the specified |url|. Returns false and does nothing
   // if custom links is not initialized, |url| is invalid, or |url| does not
   // exist in the list.

components/ntp_tiles/custom_links_manager_impl.cc

@@ -124,6 +124,35 @@ bool CustomLinksManagerImpl::UpdateLink(const GURL& url,
   return true;
 }
 
+bool CustomLinksManagerImpl::ReorderLink(const GURL& url, size_t new_pos) {
+  if (!IsInitialized() || !url.is_valid() || new_pos < 0 ||
+      new_pos >= current_links_.size()) {
+    return false;
+  }
+
+  auto curr_it = FindLinkWithUrl(url);
+  if (curr_it == current_links_.end())
+    return false;
+
+  auto new_it = current_links_.begin() + new_pos;
+  if (new_it == curr_it)
+    return false;
+
+  previous_links_ = current_links_;
+
+  // If the new position is to the left of the current position, left rotate the
+  // range [new_pos, curr_pos] until the link is first.
+  if (new_it < curr_it)
+    std::rotate(new_it, curr_it, curr_it + 1);
+  // If the new position is to the right, we only need to left rotate the range
+  // [curr_pos, new_pos] once so that the link is last.
+  else
+    std::rotate(curr_it, curr_it + 1, new_it + 1);
+
+  StoreLinks();
+  return true;
+}
+
 bool CustomLinksManagerImpl::DeleteLink(const GURL& url) {
   if (!IsInitialized() || !url.is_valid())
     return false;

components/ntp_tiles/custom_links_manager_impl.h

@@ -49,6 +49,7 @@ class CustomLinksManagerImpl : public CustomLinksManager,
   bool UpdateLink(const GURL& url,
                   const GURL& new_url,
                   const base::string16& new_title) override;
+  bool ReorderLink(const GURL& url, size_t new_pos) override;
   bool DeleteLink(const GURL& url) override;
   bool UndoAction() override;
 

components/ntp_tiles/custom_links_manager_impl_unittest.cc

@@ -34,6 +34,11 @@ const TestCaseItem kTestCase2[] = {
     {"http://foo1.com/", "Foo1"},
     {"http://foo2.com/", "Foo2"},
 };
+const TestCaseItem kTestCase3[] = {
+    {"http://foo1.com/", "Foo1"},
+    {"http://foo2.com/", "Foo2"},
+    {"http://foo3.com/", "Foo3"},
+};
 const TestCaseItem kTestCaseMax[] = {
     {"http://foo1.com/", "Foo1"}, {"http://foo2.com/", "Foo2"},
     {"http://foo3.com/", "Foo3"}, {"http://foo4.com/", "Foo4"},
@@ -278,6 +283,54 @@ TEST_F(CustomLinksManagerImplTest, UpdateLinkWhenUrlAlreadyExists) {
   EXPECT_EQ(initial_links, custom_links_->GetLinks());
 }
 
+TEST_F(CustomLinksManagerImplTest, ReorderLink) {
+  NTPTilesVector initial_tiles = FillTestTiles(kTestCase3);
+  std::vector<Link> initial_links = FillTestLinks(kTestCase3);
+  std::vector<Link> links_after_reorder1(
+      {Link{GURL(kTestCase3[2].url), base::UTF8ToUTF16(kTestCase3[2].title),
+            true},
+       Link{GURL(kTestCase3[0].url), base::UTF8ToUTF16(kTestCase3[0].title),
+            true},
+       Link{GURL(kTestCase3[1].url), base::UTF8ToUTF16(kTestCase3[1].title),
+            true}});
+  std::vector<Link> links_after_reorder2(
+      {Link{GURL(kTestCase3[0].url), base::UTF8ToUTF16(kTestCase3[0].title),
+            true},
+       Link{GURL(kTestCase3[2].url), base::UTF8ToUTF16(kTestCase3[2].title),
+            true},
+       Link{GURL(kTestCase3[1].url), base::UTF8ToUTF16(kTestCase3[1].title),
+            true}});
+
+  // Initialize.
+  ASSERT_TRUE(custom_links_->Initialize(initial_tiles));
+  ASSERT_EQ(initial_links, custom_links_->GetLinks());
+
+  // Try to call reorder with the current index. This should fail and not modify
+  // the list.
+  EXPECT_FALSE(custom_links_->ReorderLink(GURL(kTestCase3[2].url), (size_t)2));
+  EXPECT_EQ(initial_links, custom_links_->GetLinks());
+
+  // Try to call reorder with an invalid index. This should fail and not modify
+  // the list.
+  EXPECT_FALSE(custom_links_->ReorderLink(GURL(kTestCase3[2].url), (size_t)-1));
+  EXPECT_EQ(initial_links, custom_links_->GetLinks());
+  EXPECT_FALSE(custom_links_->ReorderLink(GURL(kTestCase3[2].url),
+                                          initial_links.size()));
+  EXPECT_EQ(initial_links, custom_links_->GetLinks());
+
+  // Move the last link to the front.
+  EXPECT_TRUE(custom_links_->ReorderLink(GURL(kTestCase3[2].url), (size_t)0));
+  EXPECT_EQ(links_after_reorder1, custom_links_->GetLinks());
+
+  // Move the same link to the right.
+  EXPECT_TRUE(custom_links_->ReorderLink(GURL(kTestCase3[2].url), (size_t)1));
+  EXPECT_EQ(links_after_reorder2, custom_links_->GetLinks());
+
+  // Move the same link to the end.
+  EXPECT_TRUE(custom_links_->ReorderLink(GURL(kTestCase3[2].url), (size_t)2));
+  EXPECT_EQ(initial_links, custom_links_->GetLinks());
+}
+
 TEST_F(CustomLinksManagerImplTest, DeleteLink) {
   NTPTilesVector initial_tiles;
   AddTile(&initial_tiles, kTestUrl, kTestTitle);

components/ntp_tiles/most_visited_sites.cc

@@ -315,6 +315,22 @@ bool MostVisitedSites::UpdateCustomLink(const GURL& url,
   return success;
 }
 
+bool MostVisitedSites::ReorderCustomLink(const GURL& url, size_t new_pos) {
+  if (!custom_links_ || !custom_links_enabled_)
+    return false;
+
+  // Initialize custom links if they have not been initialized yet.
+  InitializeCustomLinks();
+
+  bool success = custom_links_->ReorderLink(url, new_pos);
+  if (success) {
+    if (custom_links_action_count_ != -1)
+      custom_links_action_count_++;
+    BuildCurrentTiles();
+  }
+  return success;
+}
+
 bool MostVisitedSites::DeleteCustomLink(const GURL& url) {
   if (!custom_links_ || !custom_links_enabled_)
     return false;

components/ntp_tiles/most_visited_sites.h

@@ -184,6 +184,11 @@ class MostVisitedSites : public history::TopSitesObserver,
   bool UpdateCustomLink(const GURL& url,
                         const GURL& new_url,
                         const base::string16& new_title);
+  // Moves the custom link specified by |url| to the index |new_pos|. If |url|
+  // does not exist, or |new_pos| is invalid, returns false and does nothing.
+  // Will initialize custom links if they have not been initialized yet. Custom
+  // links must be enabled.
+  bool ReorderCustomLink(const GURL& url, size_t new_pos);
   // Deletes the custom link with the specified |url|. If |url| does not exist
   // in the custom link list, returns false and does nothing. Will initialize
   // custom links if they have not been initialized yet. Custom links must be

components/ntp_tiles/most_visited_sites_unittest.cc

@@ -276,6 +276,7 @@ class MockCustomLinksManager : public CustomLinksManager {
                bool(const GURL& url,
                     const GURL& new_url,
                     const base::string16& new_title));
+  MOCK_METHOD2(ReorderLink, bool(const GURL& url, size_t new_pos));
   MOCK_METHOD1(DeleteLink, bool(const GURL& url));
   MOCK_METHOD0(UndoAction, bool());
   MOCK_METHOD1(RegisterCallbackForOnChanged,