Selecting with shift+drag results in unexpected drag-n-drop

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

Index: third_party/WebKit/Source/core/editing/SelectionController.cpp
diff --git a/third_party/WebKit/Source/core/editing/SelectionController.cpp b/third_party/WebKit/Source/core/editing/SelectionController.cpp
index 2c317f259e65caae5930dd13894feb023c9c87b5..8924f88ce894ee30dbd8e4d5a40a555dfc77abe4 100644
--- a/third_party/WebKit/Source/core/editing/SelectionController.cpp
+++ b/third_party/WebKit/Source/core/editing/SelectionController.cpp
@@ -128,8 +128,8 @@ bool SelectionController::handleMousePressEventSingleClick(const MouseEventWithH
     if (!(innerNode && innerNode->layoutObject() && m_mouseDownMayStartSelect))
         return false;
 
-    // Extend the selection if the Shift key is down, unless the click is in a link.
-    bool extendSelection = event.event().shiftKey() && !event.isOverLink();
+    // Extend the selection if the Shift key is down, unless the click is in a link or image.
+    bool extendSelection = isExtendingSelection(event);
 
     // Don't restart the selection when the mouse is pressed on an
     // existing selection so we can allow for text dragging.
@@ -635,4 +635,12 @@ bool isLinkSelection(const MouseEventWithHitTestResults& event)
     return event.event().altKey() && event.isOverLink();
 }
 
+bool isExtendingSelection(const MouseEventWithHitTestResults& event)
+{
+    DCHECK_LE(event.event().clickCount(), 1);
+

[yosin_UTC9, 2016/06/08 01:37:21]

nit: no need to have an extra blank line here.

[tonikitoo, 2016/06/24 18:39:20]

The assert was not actually right. I removed it.

+    bool isMouseDownOnLinkOrImage = event.isOverLink() || event.hitTestResult().image();
+    return event.event().shiftKey() && !isMouseDownOnLinkOrImage;
+}
+
 } // namespace blink