Blink does not respect input.selectionStart and input.selectionEnd for some cases

Source/core/html/HTMLTextFormControlElement.cpp

Index: Source/core/html/HTMLTextFormControlElement.cpp
diff --git a/Source/core/html/HTMLTextFormControlElement.cpp b/Source/core/html/HTMLTextFormControlElement.cpp
index bf3597a17159f2e0cad756e6e8be0ffc25b2bc4c..cda62387ff36d31657fbb0608b074667030b8a56 100644
--- a/Source/core/html/HTMLTextFormControlElement.cpp
+++ b/Source/core/html/HTMLTextFormControlElement.cpp
@@ -164,12 +164,12 @@ void HTMLTextFormControlElement::updatePlaceholderVisibility(bool placeholderVal
 
 void HTMLTextFormControlElement::setSelectionStart(int start)
 {
-    setSelectionRange(start, max(start, selectionEnd()), selectionDirection());
+    setSelectionRange(start, max(start, selectionEndForJavascriptBindings()), selectionDirection());
 }
 
 void HTMLTextFormControlElement::setSelectionEnd(int end)
 {
-    setSelectionRange(min(end, selectionStart()), end, selectionDirection());
+    setSelectionRange(min(end, selectionStartForJavascriptBindings()), end, selectionDirection());
 }
 
 void HTMLTextFormControlElement::setSelectionDirection(const String& direction)
@@ -285,11 +285,10 @@ void HTMLTextFormControlElement::setSelectionRange(int start, int end, TextField
 
     end = max(end, 0);
     start = min(max(start, 0), end);
+    cacheSelection(start, end, direction);
 
-    if (!hasVisibleTextArea(renderer(), innerTextElement())) {
-        cacheSelection(start, end, direction);
+    if (!hasVisibleTextArea(renderer(), innerTextElement()))
         return;
-    }
     VisiblePosition startPosition = visiblePositionForIndex(start);
     VisiblePosition endPosition;
     if (start == end)
@@ -341,6 +340,19 @@ int HTMLTextFormControlElement::selectionStart() const
 {
     if (!isTextFormControl())
         return 0;
+    if (document().focusedElement() != this) {

[tkent, 2014/05/19 00:00:34]

We should not need to adjust the value on getting.

[harpreet.sk, 2014/05/19 11:16:52]

Only for given case we need to adjust value while getting:

We set input.selectionStart = 3 and input.selectionEnd = 5; input.value is empty
currently.

Now if we call selectionStart()/selectionEnd() it should return start/End as 0 (
all browsers return 0 ) but cache selection should still store 3 and 5 as
start/End for future.

Now if we set value of input as input.value = "Parsed" it should show
selectionStart/End as 3 and 5.

+        if (!innerTextValue().length())
+            return 0;
+        return m_cachedSelectionStart;
+    }
+
+    return computeSelectionStart();
+}
+
+int HTMLTextFormControlElement::selectionStartForJavascriptBindings() const
+{
+    if (!isTextFormControl())
+        return 0;
     if (document().focusedElement() != this)
         return m_cachedSelectionStart;
 
@@ -361,8 +373,21 @@ int HTMLTextFormControlElement::selectionEnd() const
 {
     if (!isTextFormControl())
         return 0;
+    if (document().focusedElement() != this) {
+        if (!innerTextValue().length())
+            return 0;
+        return m_cachedSelectionEnd;
+    }
+    return computeSelectionEnd();
+}
+
+int HTMLTextFormControlElement::selectionEndForJavascriptBindings() const
+{
+    if (!isTextFormControl())
+        return 0;
     if (document().focusedElement() != this)
         return m_cachedSelectionEnd;
+
     return computeSelectionEnd();
 }
 
@@ -478,9 +503,6 @@ void HTMLTextFormControlElement::selectionChanged(bool userTriggered)
     if (!renderer() || !isTextFormControl())
         return;
 
-    // selectionStart() or selectionEnd() will return cached selection when this node doesn't have focus
-    cacheSelection(computeSelectionStart(), computeSelectionEnd(), computeSelectionDirection());
-
     if (LocalFrame* frame = document().frame()) {
         if (frame->selection().isRange() && userTriggered)
             dispatchEvent(Event::createBubble(EventTypeNames::select));