Add the chrome.bluetoothLowEnergy.setAdvertisingInterval API.

chrome/common/extensions/api/bluetooth_low_energy.idl

Index: chrome/common/extensions/api/bluetooth_low_energy.idl
diff --git a/chrome/common/extensions/api/bluetooth_low_energy.idl b/chrome/common/extensions/api/bluetooth_low_energy.idl
index 0433fb3eec28fb9e9ee79ce82e214d941627e79b..b35cd98806b395692e767ed46966a6ebf90fd36d 100644
--- a/chrome/common/extensions/api/bluetooth_low_energy.idl
+++ b/chrome/common/extensions/api/bluetooth_low_energy.idl
@@ -464,6 +464,19 @@ namespace bluetoothLowEnergy {
     static void unregisterAdvertisement(long advertisementId,
         ResultCallback callback);
 
+    // Set's the interval betweeen two consecutive advertisements. Note:
+    // This is a best effort. The actual interval may vary non-trivially
+    // from the requested intervals. On some hardware, there is a minimum
+    // interval of 100ms. The minimum and maximum values cannot exceed the
+    // the range allowed by the Bluetooth 4.2 specification.
+    // |minInterval|: Minimum interval between advertisments (in
+    // milliseconds). This cannot be lower than 20ms (as per the spec).
+    // |maxInterval|: Maximum interval between advertisments (in
+    // milliseconds). This cannot be more than 10240ms (as per the spec).
+    // |callback|: Called once the interval has been set.
+    static void setAdvertisingInterval(long minInterval, long maxInterval,
+        ResultCallback callback);
+
     // Sends a response for a characteristic or descriptor read/write
     // request.
     // This function is only available if the app has both the