Fix wifi_component build with 10.9+ SDK

Use forward declaration to build on both 10.6 and 10.9 SDK and
runtime checking to make sure we don't call the wrong API.

BUG=390212

Review URL: https://codereview.chromium.org/530193004

Cr-Commit-Position: refs/heads/master@{#293911}

base/mac/sdk_forward_declarations.h

@@ -257,6 +257,51 @@ typedef NSUInteger NSWindowOcclusionState;
 - (NSWindowOcclusionState)occlusionState;
 @end
 
+// 10.6 SDK don't have CWSecurity while 10.9 SDK don't have CWSecurityMode, to
+// build with SDKs from 10.6 to 10.9 both need to be forward declared and use
+// runtime checks to ensure correct methods are used on different OS X versions.
+enum {
+   kCWSecurityNone = 0,
+   kCWSecurityWEP = 1,
+   kCWSecurityWPAPersonal = 2,
+   kCWSecurityWPAPersonalMixed = 3,
+   kCWSecurityWPA2Personal = 4,
+   kCWSecurityPersonal = 5,
+   kCWSecurityDynamicWEP = 6,
+   kCWSecurityWPAEnterprise = 7,
+   kCWSecurityWPAEnterpriseMixed = 8,
+   kCWSecurityWPA2Enterprise = 9,
+   kCWSecurityEnterprise = 10,
+   kCWSecurityUnknown = NSIntegerMax,
+};
+
+typedef NSInteger CWSecurity;
+
+@interface CWNetwork (MavericksSDK)
+@property(readonly) NSInteger rssiValue;
+- (BOOL)supportsSecurity:(CWSecurity)security;
+@end
+
+#else  // !MAC_OS_X_VERSION_10_9
+
+typedef enum {
+   kCWSecurityModeOpen = 0,
+   kCWSecurityModeWEP,
+   kCWSecurityModeWPA_PSK,
+   kCWSecurityModeWPA2_PSK,
+   kCWSecurityModeWPA_Enterprise,
+   kCWSecurityModeWPA2_Enterprise,
+   kCWSecurityModeWPS,
+   kCWSecurityModeDynamicWEP
+} CWSecurityMode;
+
+@interface CWNetwork (SnowLeopardSDK)
+@property(readonly) NSNumber* rssi;
+@property(readonly) NSNumber* securityMode;
+@end
+
+BASE_EXPORT extern "C" NSString* const kCWSSIDDidChangeNotification;
+
 #endif  // MAC_OS_X_VERSION_10_9
 
 #if !defined(MAC_OS_X_VERSION_10_10) || \

components/wifi/wifi_service_mac.mm

@@ -100,6 +100,10 @@ class WiFiServiceMac : public WiFiService {
   // Converts |CWSecurityMode| into onc::wifi::k{WPA|WEP}* security constant.
   std::string SecurityFromCWSecurityMode(CWSecurityMode security) const;
 
+  // Returns onc::wifi::k{WPA|WEP}* security constant supported by the
+  // |CWNetwork|.
+  std::string SecurityFromCWNetwork(const CWNetwork* network) const;
+
   // Converts |CWChannelBand| into Frequency constant.
   Frequency FrequencyFromCWChannelBand(CWChannelBand band) const;
 
@@ -505,9 +509,25 @@ void WiFiServiceMac::NetworkPropertiesFromCWNetwork(
   properties->frequency = FrequencyFromCWChannelBand(
       static_cast<CWChannelBand>([[network wlanChannel] channelBand]));
   properties->frequency_set.insert(properties->frequency);
+
+  // -[CWNetwork supportsSecurity:] is available from 10.7 SDK while
+  // -[CWNetwork securityMode] is deprecated and hidden as private since
+  // 10.9 SDK. The latter is kept for now to support running on 10.6. It
+  // should be removed when 10.6 support is dropped.
+  if ([network respondsToSelector:@selector(supportsSecurity:)]) {
+    properties->security = SecurityFromCWNetwork(network);
+  } else {
     properties->security = SecurityFromCWSecurityMode(
         static_cast<CWSecurityMode>([[network securityMode] intValue]));
+  }
 
+  // rssiValue property of CWNetwork is available from 10.7 SDK while
+  // -[CWNetwork rssi] is deprecated and hidden as private since 10.9 SDK.
+  // The latter is kept for now to support running on 10.6. It should be
+  // removed when 10.6 support is dropped.
+  if ([network respondsToSelector:@selector(rssiValue)])
+    properties->signal_strength = [network rssiValue];
+  else
     properties->signal_strength = [[network rssi] intValue];
 }
 
@@ -532,6 +552,31 @@ std::string WiFiServiceMac::SecurityFromCWSecurityMode(
   return onc::wifi::kWPA_EAP;
 }
 
+std::string WiFiServiceMac::SecurityFromCWNetwork(
+    const CWNetwork* network) const {
+  if ([network supportsSecurity:kCWSecurityWPAEnterprise] ||
+      [network supportsSecurity:kCWSecurityWPA2Enterprise]) {
+    return onc::wifi::kWPA_EAP;
+  }
+
+  if ([network supportsSecurity:kCWSecurityWPAPersonal] ||
+      [network supportsSecurity:kCWSecurityWPA2Personal]) {
+    return onc::wifi::kWPA_PSK;
+  }
+
+  if ([network supportsSecurity:kCWSecurityWEP])
+    return onc::wifi::kWEP_PSK;
+
+  if ([network supportsSecurity:kCWSecurityNone])
+    return onc::wifi::kSecurityNone;
+
+  // TODO(mef): Figure out correct mapping.
+  if ([network supportsSecurity:kCWSecurityDynamicWEP])
+    return onc::wifi::kWPA_EAP;
+
+  return onc::wifi::kWPA_EAP;
+}
+
 Frequency WiFiServiceMac::FrequencyFromCWChannelBand(CWChannelBand band) const {
   return band == kCWChannelBand2GHz ? kFrequency2400 : kFrequency5000;
 }