bluetooth: Return int8_t and use -128 for unknown tx power.

third_party/WebKit/LayoutTests/bluetooth/advertising-data.html

Index: third_party/WebKit/LayoutTests/bluetooth/advertising-data.html
diff --git a/third_party/WebKit/LayoutTests/bluetooth/advertising-data.html b/third_party/WebKit/LayoutTests/bluetooth/advertising-data.html
index b70cfcc7dbea89823cdef107edfcb92495ca1302..d699bcbc4c434d9f4c925cb01bb60951098fd697 100644
--- a/third_party/WebKit/LayoutTests/bluetooth/advertising-data.html
+++ b/third_party/WebKit/LayoutTests/bluetooth/advertising-data.html
@@ -16,12 +16,6 @@ test(t => { assert_true(window.testRunner instanceof Object); t.done(); },
   rssi: 0,
   expected_rssi: 0
 }, {
-  name: 'RSSI too low must result in nulled rssi.',
-  tx_power: 0,
-  expected_tx_power: 0,
-  rssi: -128,
-  expected_rssi: null
-}, {
   name: 'Low Tx Power should appear in adData.',
   tx_power: -127,
   expected_tx_power: -127,
@@ -31,15 +25,12 @@ test(t => { assert_true(window.testRunner instanceof Object); t.done(); },
   name: 'Low RSSI should appear in adData.',
   tx_power: 0,
   expected_tx_power: 0,
-  rssi: -127,
-  expected_rssi: -127
+  rssi: -128,
+  expected_rssi: -128
 }, {
   name: 'High Tx Power should appear in adData.',
-  // TODO(ortuno): According to the Bluetooth Spec Supplement, 127 is the
-  // the hightest possible valid value for Tx Power. Change to 127 when
-  // fixed: http://crbug.com/551572
-  tx_power: 126,
-  expected_tx_power: 126,
+  tx_power: 127,
+  expected_tx_power: 127,
   rssi: 0,
   expected_rssi: 0
 }, {
@@ -49,15 +40,6 @@ test(t => { assert_true(window.testRunner instanceof Object); t.done(); },
   rssi: 126,
   expected_rssi: 126
 }, {
-  // TODO(ortuno): Remove this test since 127 is both a valid Tx Power
-  // and the max value of a int8.
-  // http://crbug.com/551572
-  name: 'Tx Power too high must result in nulled txPower.',
-  tx_power: 127,
-  expected_tx_power: null,
-  rssi: 0,
-  expected_rssi: 0
-}, {
   name: 'RSSI too high must result in nulled rssi.',
   tx_power: 0,
   expected_tx_power: 0,