bluetooth: mac: Reject requestDevice promise if Mac version is <= 10.9

device/bluetooth/bluetooth_adapter_factory.cc

Index: device/bluetooth/bluetooth_adapter_factory.cc
diff --git a/device/bluetooth/bluetooth_adapter_factory.cc b/device/bluetooth/bluetooth_adapter_factory.cc
index 61aa3dc7a6abb83efac1f7bcc609e95f122d3e4b..3403b1a3cd1d7cc31465d4e42dae3a0942389174 100644
--- a/device/bluetooth/bluetooth_adapter_factory.cc
+++ b/device/bluetooth/bluetooth_adapter_factory.cc
@@ -13,6 +13,10 @@
 #include "build/build_config.h"
 #include "device/bluetooth/bluetooth_adapter.h"
 
+#if defined(OS_MACOSX)
+#include "base/mac/mac_util.h"
+#endif
+
 namespace device {
 
 namespace {
@@ -63,6 +67,24 @@ bool BluetoothAdapterFactory::IsBluetoothAdapterAvailable() {
 #endif
 }
 
+// static
+bool BluetoothAdapterFactory::IsLowEnergyAvailable() {
+  DCHECK(IsBluetoothAdapterAvailable());
+
+  // SetAdapterForTesting() may be used to provide a test or mock adapter
+  // instance even on platforms that would otherwise not support it.
+  if (default_adapter.Get())
+    return true;
+#if defined(OS_ANDROID) || defined(OS_CHROMEOS) || defined(OS_WIN) || \
+    defined(OS_LINUX)
+  return true;
+#elif defined(OS_MACOSX)
+  return base::mac::IsAtLeastOS10_10();
+#endif  // defined(OS_ANDROID) || defined(OS_CHROMEOS) || defined(OS_WIN) ||
+        // defined(OS_LINUX)
+  return false;

[sdefresne, 2016/10/05 11:08:30]

The above will expand to the following when OS_WIN is defined:

  return true;
  return false;

The Windows compiler warns because the "return false" cannot be reached.

I recommend changing this to the following:

#if defined(OS_ANDROID) || defined(OS_CHROMEOS) || defined(OS_WIN) || \
     defined(OS_LINUX)
  return true;
#elif defined(OS_MACOSX)
  return base::mac::IsAtLeastOS10_10();
#else
  return false;
#endif  // defined(OS_ANDROID) || defined(OS_CHROMEOS) || defined(OS_WIN) ||
        // defined(OS_LINUX)

Or if you do want to have an #else, use a local variable (but note that this
will cause a assignment has no effect when building with clang static analyser):

bool is_low_energy_available = false;
#if defined(OS_ANDROID) || defined(OS_CHROMEOS) || defined(OS_WIN) || \
     defined(OS_LINUX)
  is_low_energy_available = true;
#elif defined(OS_MACOSX)
  is_low_energy_available = base::mac::IsAtLeastOS10_10();
#endif  // defined(OS_ANDROID) || defined(OS_CHROMEOS) || defined(OS_WIN) ||
        // defined(OS_LINUX)
  return is_low_energy_available;

+}
+
 // static
 void BluetoothAdapterFactory::GetAdapter(const AdapterCallback& callback) {
   DCHECK(IsBluetoothAdapterAvailable());