Make StylePropertyMap::SetProperty take a const CSSValue& instead of ptr

Made StylePropertyMap::setProperty take a const CSSValue& instead of a
const CSSValue*. This is more semantically correct and safe since
StylePropertyMaps cannot store nullptrs, and is also an attempt to fix
a strange performance issue caused from introducing const CSSValue*s.

BUG=526586
R=sashab@chromium.org
Signed-off-by: Zhuoyu Qian <zhuoyu.qian@samsung.com>
Change-Id: I30f612d69ee944e9df9d591fd6585512aea7d0ac
Reviewed-on: https://chromium-review.googlesource.com/835907Reviewed-by: Sasha Morrissey <sashab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526443}

third_party/WebKit/Source/core/css/cssom/InlineStylePropertyMap.cpp

@@ -21,8 +21,8 @@ const CSSValue* InlineStylePropertyMap::GetCustomProperty(
 }
 
 void InlineStylePropertyMap::SetProperty(CSSPropertyID property_id,
-                                         const CSSValue* value) {
-  owner_element_->SetInlineStyleProperty(property_id, *value);
+                                         const CSSValue& value) {
+  owner_element_->SetInlineStyleProperty(property_id, value);
 }
 
 void InlineStylePropertyMap::RemoveProperty(CSSPropertyID property_id) {

third_party/WebKit/Source/core/css/cssom/InlineStylePropertyMap.h

@@ -25,7 +25,7 @@ class CORE_EXPORT InlineStylePropertyMap final : public StylePropertyMap {
   const CSSValue* GetProperty(CSSPropertyID) override;
   const CSSValue* GetCustomProperty(AtomicString) override;
   void ForEachProperty(const IterationCallback&) override;
-  void SetProperty(CSSPropertyID, const CSSValue*) override;
+  void SetProperty(CSSPropertyID, const CSSValue&) override;
   void RemoveProperty(CSSPropertyID) override;
   void RemoveCustomProperty(const AtomicString&);
 

third_party/WebKit/Source/core/css/cssom/StylePropertyMap.cpp

@@ -122,7 +122,7 @@ void StylePropertyMap::set(const ExecutionContext* execution_context,
     return;
   }
 
-  SetProperty(property_id, result);
+  SetProperty(property_id, *result);
 }
 
 void StylePropertyMap::append(const ExecutionContext* execution_context,
@@ -165,7 +165,7 @@ void StylePropertyMap::append(const ExecutionContext* execution_context,
     current_value->Append(*value);
   }
 
-  SetProperty(property_id, current_value);
+  SetProperty(property_id, *current_value);
 }
 
 void StylePropertyMap::remove(const String& property_name,

third_party/WebKit/Source/core/css/cssom/StylePropertyMap.h

@@ -34,7 +34,7 @@ class CORE_EXPORT StylePropertyMap : public StylePropertyMapReadonly {
               ExceptionState&);
 
  protected:
-  virtual void SetProperty(CSSPropertyID, const CSSValue*) = 0;
+  virtual void SetProperty(CSSPropertyID, const CSSValue&) = 0;
   virtual void RemoveProperty(CSSPropertyID) = 0;
   virtual void RemoveCustomProperty(const AtomicString&) = 0;