Make ResourceResponse's cached CacheControlHeader mutable.

third_party/WebKit/Source/platform/network/ResourceResponse.h

Index: third_party/WebKit/Source/platform/network/ResourceResponse.h
diff --git a/third_party/WebKit/Source/platform/network/ResourceResponse.h b/third_party/WebKit/Source/platform/network/ResourceResponse.h
index e0276241609c1ef2675375f9dfbaf17fb9016573..cd3cf5f766d6cfcb90dff38ff1c00e473eba185c 100644
--- a/third_party/WebKit/Source/platform/network/ResourceResponse.h
+++ b/third_party/WebKit/Source/platform/network/ResourceResponse.h
@@ -138,12 +138,12 @@ public:
 
     // These functions return parsed values of the corresponding response headers.
     // NaN means that the header was not present or had invalid value.
-    bool cacheControlContainsNoCache();
-    bool cacheControlContainsNoStore();
-    bool cacheControlContainsMustRevalidate();
+    bool cacheControlContainsNoCache() const;
+    bool cacheControlContainsNoStore() const;
+    bool cacheControlContainsMustRevalidate() const;
     bool hasCacheValidatorFields() const;
-    double cacheControlMaxAge();
-    double cacheControlStaleWhileRevalidate();
+    double cacheControlMaxAge() const;
+    double cacheControlStaleWhileRevalidate() const;
     double date() const;
     double age() const;
     double expires() const;
@@ -271,7 +271,7 @@ private:
 
     bool m_isNull : 1;
 
-    CacheControlHeader m_cacheControlHeader;
+    mutable CacheControlHeader m_cacheControlHeader;
 
     mutable bool m_haveParsedAgeHeader : 1;
     mutable bool m_haveParsedDateHeader : 1;