Experimental CompressibleString UMA

third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp

Index: third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp b/third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp
index a3d51c99a7cffe26b14c255ae334807e9d4aaa9f..0fed16ac2f70c1bcf3e7d2cad71108ac6a4b23e6 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp
@@ -48,7 +48,7 @@ struct StringTraits<String> {
 
 template<>
 struct StringTraits<AtomicString> {
-    static const AtomicString& fromStringResource(WebCoreStringResourceBase* resource)
+    static AtomicString fromStringResource(WebCoreStringResourceBase* resource)
     {
         return resource->atomicString();
     }
@@ -107,10 +107,17 @@ StringType v8StringToWebCoreString(v8::Local<v8::String> v8String, ExternalMode
         v8::String::ExternalStringResourceBase* resource = v8String->GetExternalStringResourceBase(&encoding);
         if (LIKELY(!!resource)) {
             WebCoreStringResourceBase* base;
-            if (encoding == v8::String::ONE_BYTE_ENCODING)
-                base = static_cast<WebCoreStringResource8*>(resource);
-            else
-                base = static_cast<WebCoreStringResource16*>(resource);
+            if (UNLIKELY(resource->IsCompressible())) {
+                if (encoding == v8::String::ONE_BYTE_ENCODING)
+                    base = static_cast<WebCoreCompressibleStringResource8*>(resource);
+                else
+                    base = static_cast<WebCoreCompressibleStringResource16*>(resource);
+            } else {
+                if (encoding == v8::String::ONE_BYTE_ENCODING)
+                    base = static_cast<WebCoreStringResource8*>(resource);
+                else
+                    base = static_cast<WebCoreStringResource16*>(resource);
+            }
             return StringTraits<StringType>::fromStringResource(base);
         }
     }