Devtools[LayoutEditor]: Correctly handle new values

Source/core/inspector/LayoutEditor.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/inspector/LayoutEditor.h"
 
 #include "core/css/CSSComputedStyleDeclaration.h"
 #include "core/dom/NodeComputedStyle.h"
 #include "core/frame/FrameView.h"
@@ skipping 98 matching lines @@
     result.setP3(projection(projectOn.p3(), orthogonals.p3(), translatePoint(origin.p3(), orthogonals.p1(), distance)));
     result.setP4(projection(projectOn.p4(), orthogonals.p4(), translatePoint(origin.p4(), orthogonals.p2(), distance)));
     return result;
 }
 
 bool isMutableUnitType(CSSPrimitiveValue::UnitType unitType)
 {
     return unitType == CSSPrimitiveValue::UnitType::Pixels || unitType == CSSPrimitiveValue::UnitType::Ems || unitType == CSSPrimitiveValue::UnitType::Percentage || unitType == CSSPrimitiveValue::UnitType::Rems;
 }
 
+String truncateZeroes(const String& number)
+{
+    if (!number.contains('.'))
+        return number;
+
+    int removeCount = 0;
+    while (number[number.length() - removeCount - 1] == '0')
+        removeCount++;
+
+    if (number[number.length() - removeCount - 1] == '.')
+        removeCount++;
+
+    return number.left(number.length() - removeCount);
+}
+
+float toValidValue(CSSPropertyID propertyId, float newValue)
+{
+    if (CSSPropertyPaddingBottom <= propertyId && propertyId <= CSSPropertyPaddingTop)
+        return newValue >= 0 ? newValue : 0;
+
+    return newValue;
+}
 } // namespace
 
 LayoutEditor::LayoutEditor(InspectorCSSAgent* cssAgent)
     : m_element(nullptr)
     , m_cssAgent(cssAgent)
     , m_changingProperty(CSSPropertyInvalid)
     , m_propertyInitialValue(0)
 {
 }
 
@@ skipping 103 matching lines @@
         ASSERT_NOT_REACHED();
         break;
     }
     m_propertyInitialValue = cssValue ? cssValue->getFloatValue() : 0;
 }
 
 void LayoutEditor::overlayPropertyChanged(float cssDelta)
 {
     if (m_changingProperty && m_factor) {
         String errorString;
-        m_cssAgent->setCSSPropertyValue(&errorString, m_element.get(), m_changingProperty, String::format("%.2f", cssDelta / m_factor + m_propertyInitialValue) + CSSPrimitiveValue::unitTypeToString(m_valueUnitType));
+        float newValue = toValidValue(m_changingProperty, cssDelta / m_factor + m_propertyInitialValue);
+        m_cssAgent->setCSSPropertyValue(&errorString, m_element.get(), m_changingProperty, truncateZeroes(String::format("%.2f", newValue)) + CSSPrimitiveValue::unitTypeToString(m_valueUnitType));
     }
 }
 
 void LayoutEditor::overlayEndedPropertyChange()
 {
     m_changingProperty = CSSPropertyInvalid;
     m_propertyInitialValue = 0;
     m_factor = 0;
     m_valueUnitType = CSSPrimitiveValue::UnitType::Unknown;
 }
 
 } // namespace blink