Printing API: Add additional PrinterSetupSource entry

Bug: 996785
Change-Id: Ib8d28e3651a9b39107f242883983a13fa13eedb6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1930811
Commit-Queue: Sean Kau <skau@chromium.org>
Reviewed-by: Sean Kau <skau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#718385}

chrome/browser/chromeos/printing/printer_configurer.h

@@ -61,7 +61,8 @@ enum class PrinterSetupSource {
   kSettings = 1,           // Printer was setup from Settings.
   kAutoUsbConfigurer = 2,  // Printer was setup by automatic USB configurer.
   kArcPrintService = 3,    // Printer was setup by arc print service.
-  kMaxValue = kArcPrintService,
+  kExtensionApi = 4,       // Printer was setup via Extensions API.
+  kMaxValue = kExtensionApi,
 };
 
 using PrinterSetupCallback = base::OnceCallback<void(PrinterSetupResult)>;

tools/metrics/histograms/enums.xml

@@ -51043,6 +51043,7 @@ Called by update_net_trust_anchors.py.-->
   <int value="1" label="Printer was setup from Settings"/>
   <int value="2" label="Printer was setup by automatic USB configurer"/>
   <int value="3" label="Printer was setup by arc print service"/>
+  <int value="4" label="Printer was setup via Extensions API"/>
 </enum>
 
 <enum name="PrintJobResult">