Remove 'String::append' from some of the blink source.

Source/core/inspector/InspectorCSSAgent.cpp

Index: Source/core/inspector/InspectorCSSAgent.cpp
diff --git a/Source/core/inspector/InspectorCSSAgent.cpp b/Source/core/inspector/InspectorCSSAgent.cpp
old mode 100644
new mode 100755
index 03096a8802c116b5882ab7a9e05d13d6c841c3fc..371f3bf4819a2295b5581fcef2547866074108fb
--- a/Source/core/inspector/InspectorCSSAgent.cpp
+++ b/Source/core/inspector/InspectorCSSAgent.cpp
@@ -420,7 +420,7 @@ public:
         m_oldText = oldText.stripWhiteSpace();
         // FIXME: remove this once the model handles this case.
         if (!m_oldText.endsWith(';'))
-            m_oldText.append(';');
+            m_oldText = oldText.stripWhiteSpace() + ";";
         return result;
     }