Reduce wtf/RefPtr.h

This CL contains:
 - Moves WTF::GetPtr overload for RefPtr to wtf/GetPtr.h,
 - Moves RefPtrValuePeeker to wtf/HashFunctions.h
 - Merges WTF::AdoptRef and base::AdoptRef.
as a preparation of RefPtr.h removal.

Bug: 763844
Change-Id: Iac2cfe6af0304ed4ea180f6ed50a08e9065672b9
Reviewed-on: https://chromium-review.googlesource.com/727683Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510145}

third_party/WebKit/Source/platform/wtf/GetPtr.h

@@ -21,6 +21,9 @@
 #ifndef WTF_GetPtr_h
 #define WTF_GetPtr_h
 
+template <typename>
+class scoped_refptr;
+
 namespace WTF {
 
 template <typename T>
@@ -33,6 +36,11 @@ inline T* GetPtr(T& p) {
   return &p;
 }
 
+template <typename T>
+inline T* GetPtr(const scoped_refptr<T>& p) {
+  return p.get();
+}
+
 }  // namespace WTF
 
 #endif  // WTF_GetPtr_h

third_party/WebKit/Source/platform/wtf/HashTraits.h

@@ -27,6 +27,7 @@
 #include <memory>
 #include <type_traits>
 #include <utility>
+#include "platform/wtf/Allocator.h"
 #include "platform/wtf/Forward.h"
 #include "platform/wtf/HashFunctions.h"
 #include "platform/wtf/HashTableDeletedValueType.h"
@@ -219,6 +220,20 @@ struct HashTraits<RefPtr<P>> : SimpleClassHashTraits<RefPtr<P>> {
                 "Unexpected RefPtr size."
                 " RefPtr needs to be single pointer to support deleted value.");
 
+  class RefPtrValuePeeker {
+    DISALLOW_NEW();
+
+   public:
+    ALWAYS_INLINE RefPtrValuePeeker(P* p) : ptr_(p) {}
+    template <typename U>
+    RefPtrValuePeeker(const RefPtr<U>& p) : ptr_(p.get()) {}
+
+    ALWAYS_INLINE operator P*() const { return ptr_; }
+
+   private:
+    P* ptr_;
+  };
+
   typedef std::nullptr_t EmptyValueType;
   static EmptyValueType EmptyValue() { return nullptr; }
 
@@ -234,7 +249,7 @@ struct HashTraits<RefPtr<P>> : SimpleClassHashTraits<RefPtr<P>> {
     *reinterpret_cast<void**>(&slot) = reinterpret_cast<void*>(-1);
   }
 
-  typedef RefPtrValuePeeker<P> PeekInType;
+  typedef RefPtrValuePeeker PeekInType;
   typedef RefPtr<P>* IteratorGetType;
   typedef const RefPtr<P>* IteratorConstGetType;
   typedef RefPtr<P>& IteratorReferenceType;

third_party/WebKit/Source/platform/wtf/RefPtr.h

@@ -23,37 +23,13 @@
 #define WTF_RefPtr_h
 
 #include "base/memory/scoped_refptr.h"
-#include "platform/wtf/Allocator.h"
 
 namespace WTF {
 
 template <typename T>
 using RefPtr = scoped_refptr<T>;
 
-template <typename T>
-inline T* GetPtr(const RefPtr<T>& p) {
-  return p.get();
-}
-
-template <typename T>
-class RefPtrValuePeeker {
-  DISALLOW_NEW();
-
- public:
-  ALWAYS_INLINE RefPtrValuePeeker(T* p) : ptr_(p) {}
-  template <typename U>
-  RefPtrValuePeeker(const RefPtr<U>& p) : ptr_(p.get()) {}
-
-  ALWAYS_INLINE operator T*() const { return ptr_; }
-
- private:
-  T* ptr_;
-};
-
-template <typename T>
-RefPtr<T> AdoptRef(T* p) {
-  return RefPtr<T>(base::AdoptRef(p));
-}
+using base::AdoptRef;
 
 template <typename T>
 RefPtr<T> WrapRefPtr(T* ptr) {