Introduce firstEditablePositionAfterPositionInRoot()

This patch introduces |firstEditablePositionAfterPositionInRoot()| as pair of
|lastEditablePositionBeforePositionInRoot()| to make debugging easier for
improving code health.

This patch is a preparation of making selection to handle granularity for web
component, http://crrev.com/1277863002

BUG=513568
TEST=n/a; No behavior changes

Review URL: https://codereview.chromium.org/1316063002

git-svn-id: svn://svn.chromium.org/blink/trunk@201220 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/editing/EditingUtilities.cpp

@@ -453,28 +453,44 @@ PositionInComposedTree previousVisuallyDistinctCandidate(const PositionInCompose
 }
 
 VisiblePosition firstEditableVisiblePositionAfterPositionInRoot(const Position& position, ContainerNode* highestRoot)
+{
+    return VisiblePosition(firstEditablePositionAfterPositionInRoot(position, highestRoot));
+}
+
+template <typename Strategy>
+PositionAlgorithm<Strategy> firstEditablePositionAfterPositionInRootAlgorithm(const PositionAlgorithm<Strategy>& position, Node* highestRoot)
 {
     // position falls before highestRoot.
-    if (comparePositions(position, firstPositionInNode(highestRoot)) == -1 && highestRoot->hasEditableStyle())
-        return VisiblePosition(firstPositionInNode(highestRoot));
+    if (position.compareTo(PositionAlgorithm<Strategy>::firstPositionInNode(highestRoot)) == -1 && highestRoot->hasEditableStyle())
+        return PositionAlgorithm<Strategy>::firstPositionInNode(highestRoot);
 
-    Position editablePosition = position;
+    PositionAlgorithm<Strategy> editablePosition = position;
 
     if (position.anchorNode()->treeScope() != highestRoot->treeScope()) {
         Node* shadowAncestor = highestRoot->treeScope().ancestorInThisScope(editablePosition.anchorNode());
         if (!shadowAncestor)
-            return VisiblePosition();
+            return PositionAlgorithm<Strategy>();
 
-        editablePosition = positionAfterNode(shadowAncestor);
+        editablePosition = PositionAlgorithm<Strategy>::afterNode(shadowAncestor);
     }
 
     while (editablePosition.anchorNode() && !isEditablePosition(editablePosition) && editablePosition.anchorNode()->isDescendantOf(highestRoot))
-        editablePosition = isAtomicNode(editablePosition.anchorNode()) ? positionInParentAfterNode(*editablePosition.anchorNode()) : nextVisuallyDistinctCandidate(editablePosition);
+        editablePosition = isAtomicNode(editablePosition.anchorNode()) ? PositionAlgorithm<Strategy>::inParentAfterNode(*editablePosition.anchorNode()) : nextVisuallyDistinctCandidate(editablePosition);
 
     if (editablePosition.anchorNode() && editablePosition.anchorNode() != highestRoot && !editablePosition.anchorNode()->isDescendantOf(highestRoot))
-        return VisiblePosition();
+        return PositionAlgorithm<Strategy>();
 
-    return VisiblePosition(editablePosition);
+    return editablePosition;
+}
+
+Position firstEditablePositionAfterPositionInRoot(const Position& position, Node* highestRoot)
+{
+    return firstEditablePositionAfterPositionInRootAlgorithm<EditingStrategy>(position, highestRoot);
+}
+
+PositionInComposedTree firstEditablePositionAfterPositionInRoot(const PositionInComposedTree& position, Node* highestRoot)
+{
+    return firstEditablePositionAfterPositionInRootAlgorithm<EditingInComposedTreeStrategy>(position, highestRoot);
 }
 
 VisiblePosition lastEditableVisiblePositionBeforePositionInRoot(const Position& position, ContainerNode* highestRoot)

third_party/WebKit/Source/core/editing/EditingUtilities.h

@@ -180,7 +180,9 @@ inline Position lastPositionInOrAfterNode(Node* node)
     return Position::lastPositionInOrAfterNode(node);
 }
 
+CORE_EXPORT Position firstEditablePositionAfterPositionInRoot(const Position&, Node*);
 Position lastEditablePositionBeforePositionInRoot(const Position&, Node*);
+CORE_EXPORT PositionInComposedTree firstEditablePositionAfterPositionInRoot(const PositionInComposedTree&, Node*);
 PositionInComposedTree lastEditablePositionBeforePositionInRoot(const PositionInComposedTree&, Node*);
 
 // Move up or down the DOM by one position.

third_party/WebKit/Source/core/editing/EditingUtilitiesTest.cpp

@@ -12,6 +12,25 @@ namespace blink {
 class EditingUtilitiesTest : public EditingTestBase {
 };
 
+TEST_F(EditingUtilitiesTest, firstEditablePositionAfterPositionInRoot)
+{
+    const char* bodyContent = "<p id='host' contenteditable><b id='one'></b><b id='two'>22</b></p>";
+    const char* shadowContent = "<content select=#two></content><content select=#one></content><b id='three'>333</b>";
+    setBodyContent(bodyContent);
+    RefPtrWillBeRawPtr<ShadowRoot> shadowRoot = setShadowContent(shadowContent);
+    updateLayoutAndStyleForPainting();
+    Node* host = document().getElementById("host");
+    Node* one = document().getElementById("one");
+    Node* three = shadowRoot->getElementById("three");
+
+    EXPECT_EQ(Position(one, 0), firstEditablePositionAfterPositionInRoot(Position(one, 0), host));
+
+    EXPECT_EQ(PositionInComposedTree(one, 0), firstEditablePositionAfterPositionInRoot(PositionInComposedTree(one, 0), host));
+
+    EXPECT_EQ(Position::firstPositionInNode(host), firstEditablePositionAfterPositionInRoot(Position(three, 0), host));
+    EXPECT_EQ(PositionInComposedTree::afterNode(host), firstEditablePositionAfterPositionInRoot(PositionInComposedTree(three, 0), host));
+}
+
 TEST_F(EditingUtilitiesTest, enclosingNodeOfType)
 {
     const char* bodyContent = "<p id='host'><b id='one'>11</b></p>";