Change return value of FrameSelection::modify() to prevent unnecessary window scrolling

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

Index: third_party/WebKit/Source/core/editing/FrameSelectionTest.cpp
diff --git a/third_party/WebKit/Source/core/editing/FrameSelectionTest.cpp b/third_party/WebKit/Source/core/editing/FrameSelectionTest.cpp
index c4473e3b63d7bb1d1820d0663113dfb84a3fccc2..b3ddbb076d0669b78030aed848a9f34f4874d0a8 100644
--- a/third_party/WebKit/Source/core/editing/FrameSelectionTest.cpp
+++ b/third_party/WebKit/Source/core/editing/FrameSelectionTest.cpp
@@ -178,6 +178,24 @@ TEST_F(FrameSelectionTest, ModifyExtendWithFlatTree)
     EXPECT_EQ(PositionInFlatTree(two, 3), visibleSelectionInFlatTree().end());
 }
 
+TEST_F(FrameSelectionTest, ModifyWithUserTriggered)
+{
+    setBodyContent("<div id=sample>abc</div>");
+    Element* sample = document().getElementById("sample");
+    const Position endOfText(sample->firstChild(), 3);
+    selection().setSelection(VisibleSelection(endOfText));
+
+    EXPECT_FALSE(selection().modify(FrameSelection::AlterationMove, DirectionForward, CharacterGranularity, NotUserTriggered))
+        << "Selection.modify() returns false for user triggered call when selection isn't modified.";

[Xiaocheng, 2016/08/05 01:51:25]

non-user-triggered call

Reference: https://en.wikipedia.org/wiki/Hyphen#Compound_modifiers

[yosin_UTC9, 2016/08/05 04:03:12]

Done

+    EXPECT_EQ(endOfText, selection().start())
+        << "Selection isn't modified";
+
+    EXPECT_TRUE(selection().modify(FrameSelection::AlterationMove, DirectionForward, CharacterGranularity, UserTriggered))
+        << "Selection.modify() returns true for user triggered call";

[Xiaocheng, 2016/08/05 01:51:25]

ditto: user-triggered call

[yosin_UTC9, 2016/08/05 04:03:12]

Done.

+    EXPECT_EQ(endOfText, selection().start())
+        << "Selection isn't modified";
+}
+
 TEST_F(FrameSelectionTest, MoveRangeSelectionTest)
 {
     // "Foo Bar Baz,"