Remove lazy evaluation of HTMLTextAreaElement::value.

Remove it for cleaner code, and preparation to fix crbug.com/706370.

The lazy evaluation isn't very helpful because children of innerEditor is
typically 0 or one Text node and an optional trailing <br>. In such case,
innerEditorValue() can just return Text::data(), and it's a cheap operation.

BUG=706370

Review-Url: https://codereview.chromium.org/2803483005
Cr-Commit-Position: refs/heads/master@{#461998}

third_party/WebKit/Source/core/html/HTMLTextAreaElement.cpp

@@ -76,7 +76,6 @@ HTMLTextAreaElement::HTMLTextAreaElement(Document& document)
       m_cols(defaultCols),
       m_wrap(SoftWrap),
       m_isDirty(false),
-      m_valueIsUpToDate(true),
       m_isPlaceholderVisible(false) {}
 
 HTMLTextAreaElement* HTMLTextAreaElement::create(Document& document) {
@@ -287,7 +286,7 @@ void HTMLTextAreaElement::subtreeHasChanged() {
 #endif
   addPlaceholderBreakElementIfNecessary();
   setChangedSinceLastFormControlChangeEvent(true);
-  m_valueIsUpToDate = false;
+  updateValue();
   setNeedsValidityCheck();
   setAutofilled(false);
   updatePlaceholderVisibility();
@@ -360,19 +359,14 @@ String HTMLTextAreaElement::sanitizeUserInputValue(const String& proposedValue,
   return proposedValue.left(i);
 }
 
-void HTMLTextAreaElement::updateValue() const {
-  if (m_valueIsUpToDate)
-    return;
-
+void HTMLTextAreaElement::updateValue() {
   m_value = innerEditorValue();
-  const_cast<HTMLTextAreaElement*>(this)->m_valueIsUpToDate = true;
-  const_cast<HTMLTextAreaElement*>(this)->notifyFormStateChanged();
+  notifyFormStateChanged();
   m_isDirty = true;
-  const_cast<HTMLTextAreaElement*>(this)->updatePlaceholderVisibility();
+  updatePlaceholderVisibility();
 }
 
 String HTMLTextAreaElement::value() const {
-  updateValue();
   return m_value;
 }
 
@@ -443,11 +437,6 @@ void HTMLTextAreaElement::setValueCommon(
   }
 }
 
-void HTMLTextAreaElement::setInnerEditorValue(const String& value) {
-  TextControlElement::setInnerEditorValue(value);
-  m_valueIsUpToDate = true;
-}
-
 String HTMLTextAreaElement::defaultValue() const {
   StringBuilder value;
 

third_party/WebKit/Source/core/html/HTMLTextAreaElement.h

@@ -78,8 +78,7 @@ class CORE_EXPORT HTMLTextAreaElement final : public TextControlElement {
 
   void handleBeforeTextInsertedEvent(BeforeTextInsertedEvent*) const;
   static String sanitizeUserInputValue(const String&, unsigned maxLength);
-  void updateValue() const;
-  void setInnerEditorValue(const String&) override;
+  void updateValue();
   void setNonDirtyValue(const String&);
   void setValueCommon(const String&,
                       TextFieldEventBehavior,
@@ -148,7 +147,6 @@ class CORE_EXPORT HTMLTextAreaElement final : public TextControlElement {
   WrapMethod m_wrap;
   mutable String m_value;
   mutable bool m_isDirty;
-  bool m_valueIsUpToDate;
   unsigned m_isPlaceholderVisible : 1;
   String m_suggestedValue;
 };

third_party/WebKit/Source/core/html/TextControlElement.cpp

@@ -831,6 +831,20 @@ String TextControlElement::innerEditorValue() const {
   if (!innerEditor || !isTextControl())
     return emptyString;
 
+  // Typically, innerEditor has 0 or one Text node followed by 0 or one <br>.
+  if (!innerEditor->hasChildren())
+    return emptyString;
+  Node& firstChild = *innerEditor->firstChild();
+  if (firstChild.isTextNode()) {
+    Node* secondChild = firstChild.nextSibling();
+    if (!secondChild)
+      return toText(firstChild).data();
+    if (!secondChild->nextSibling() && isHTMLBRElement(*secondChild))
+      return toText(firstChild).data();
+  } else if (!firstChild.nextSibling() && isHTMLBRElement(firstChild)) {
+    return emptyString;
+  }
+
   StringBuilder result;
   for (Node& node : NodeTraversal::inclusiveDescendantsOf(*innerEditor)) {
     if (isHTMLBRElement(node)) {