bluetooth: macOS: Adding histograms for NSError values

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 8175033a9fc2daf4e31daee616ec6363b9e08221..b67499558df72034284f15da95c23f9223ae0686 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -6213,6 +6213,19 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram base="true" name="Bluetooth.MacOS.Errors"
+    enum="MacOSBluetoothOperationsResult">
+<!-- Name completed by histogram_suffixes name="WebBluetoothMacOSAPIs" -->
+
+  <owner>scheib@chromium.org</owner>
+  <owner>device-dev@chromium.org</owner>
+  <summary>
+    Records how many times each macOS GATT error has occured. The results will
+    be used to determine how commun this errors are and if we need to provide
+    better error messages to the users.
+  </summary>
+</histogram>
+
 <histogram name="Bluetooth.PairingMethod" enum="BluetoothPairingMethod">
   <owner>keybuk@chromium.org</owner>
   <summary>
@@ -100017,6 +100030,24 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <affected-histogram name="WebApk.ShellApkVersion"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="WebBluetoothMacOSAPIs" separator=".">
+  <suffix name="DidFailToConnectToPeripheral"
+      label="Failed to connect to peripheral"/>
+  <suffix name="DidDisconnectPeripheral" label="Disconnected from peripheral"/>
+  <suffix name="DidDiscoverPrimaryServices"
+      label="Discovered primary services"/>
+  <suffix name="DidDiscoverCharacteristics" label="Discovered characteristics"/>
+  <suffix name="DidUpdateValue" label="Updated value"/>

[scheib, 2017/08/15 22:20:28]

Updated value for characteristic

[jlebel, 2017/08/15 23:05:49]

Done.

+  <suffix name="DidWriteValue" label="Wrote value value"/>
+  <suffix name="DidUpdateNotificationState" label="Updated notification state"/>
+  <suffix name="DidDiscoverDescriptors" label="Discovered descriptors"/>
+  <suffix name="DidUpdateValueForDescriptor"
+      label="Updated value for descriptor"/>
+  <suffix name="DidWriteValueForDescriptor"
+      label="Wrote value value for descriptor"/>
+  <affected-histogram name="Bluetooth.MacOS.Errors"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="WebFontFamily" separator="_">
   <suffix name="roboto" label="Roboto font"/>
   <suffix name="opensans" label="Open Sans font"/>