Create a nicer interface for base::mac::GetValueFromDictionary

base/mac/foundation_util.mm

Index: base/mac/foundation_util.mm
diff --git a/base/mac/foundation_util.mm b/base/mac/foundation_util.mm
index 8a4ce471765e1157886e293ae4c7b9007ccc24f7..777836ae9c5eaec094a29dd0c8234923983a4762 100644
--- a/base/mac/foundation_util.mm
+++ b/base/mac/foundation_util.mm
@@ -348,6 +348,41 @@ CF_CAST_DEFN(CFNumber);
 CF_CAST_DEFN(CFSet);
 CF_CAST_DEFN(CFString);
 
+#define GET_VAL_FROM_DICT_DEFN(TypeCF) \
+template<> TypeCF##Ref \
+GetValueFromDictionary<TypeCF##Ref>(CFDictionaryRef dict, CFStringRef key) { \
+  CFTypeRef val = CFDictionaryGetValue(dict, key); \
+  TypeCF##Ref value = base::mac::CFCast<TypeCF##Ref>(val); \
+  if (!val) \
+    return value; \
+  if (!value) { \
+    ScopedCFTypeRef<CFStringRef> expected_type_ref( \
+        CFCopyTypeIDDescription(TypeCF##GetTypeID())); \
+    ScopedCFTypeRef<CFStringRef> actual_type_ref( \
+        CFCopyTypeIDDescription(CFGetTypeID(val))); \
+    DLOG(WARNING) << "Expected value for key " \
+                 << base::SysCFStringRefToUTF8(key) \
+                 << " to be " \
+                 << base::SysCFStringRefToUTF8(expected_type_ref) \
+                 << " but it was " \
+                 << base::SysCFStringRefToUTF8(actual_type_ref) \
+                 << " instead"; \
+    return NULL; \
+  } \
+  return value; \
+}
+
+GET_VAL_FROM_DICT_DEFN(CFArray);
+GET_VAL_FROM_DICT_DEFN(CFBag);
+GET_VAL_FROM_DICT_DEFN(CFBoolean);
+GET_VAL_FROM_DICT_DEFN(CFData);
+GET_VAL_FROM_DICT_DEFN(CFDate);
+GET_VAL_FROM_DICT_DEFN(CFDictionary);
+GET_VAL_FROM_DICT_DEFN(CFNull);
+GET_VAL_FROM_DICT_DEFN(CFNumber);
+GET_VAL_FROM_DICT_DEFN(CFSet);
+GET_VAL_FROM_DICT_DEFN(CFString);
+
 }  // namespace mac
 }  // namespace base