Add an UMA histogram for WebUSB function calls.

third_party/WebKit/Source/modules/webusb/USB.cpp

Index: third_party/WebKit/Source/modules/webusb/USB.cpp
diff --git a/third_party/WebKit/Source/modules/webusb/USB.cpp b/third_party/WebKit/Source/modules/webusb/USB.cpp
index 8882221fd6e54b98e95f2c723043a10df17eb703..f031a0e67df43a78f5815f70d9f3ab7c6a4a3b72 100644
--- a/third_party/WebKit/Source/modules/webusb/USB.cpp
+++ b/third_party/WebKit/Source/modules/webusb/USB.cpp
@@ -9,6 +9,7 @@
 #include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
+#include "core/frame/UseCounter.h"
 #include "device/usb/public/interfaces/device.mojom-blink.h"
 #include "modules/EventTargetModules.h"
 #include "modules/webusb/USBConnectionEvent.h"
@@ -78,13 +79,16 @@ void USB::dispose()
 
 ScriptPromise USB::getDevices(ScriptState* scriptState)
 {
+    ExecutionContext* executionContext = scriptState->getExecutionContext();
+    UseCounter::count(executionContext, UseCounter::UsbGetDevices);
+
     ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
     if (!m_deviceManager) {
         resolver->reject(DOMException::create(NotSupportedError));
     } else {
         String errorMessage;
-        if (!scriptState->getExecutionContext()->isSecureContext(errorMessage)) {
+        if (!executionContext->isSecureContext(errorMessage)) {
             resolver->reject(DOMException::create(SecurityError, errorMessage));
         } else {
             m_deviceManagerRequests.add(resolver);
@@ -96,11 +100,14 @@ ScriptPromise USB::getDevices(ScriptState* scriptState)
 
 ScriptPromise USB::requestDevice(ScriptState* scriptState, const USBDeviceRequestOptions& options)
 {
+    ExecutionContext* executionContext = scriptState->getExecutionContext();
+    UseCounter::count(executionContext, UseCounter::UsbRequestDevice);
+
     ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
 
     if (!m_chooserService) {
-        LocalFrame* frame = getExecutionContext() ? toDocument(getExecutionContext())->frame() : nullptr;
+        LocalFrame* frame = executionContext->isDocument() ? toDocument(executionContext)->frame() : nullptr;
         if (!frame) {
             resolver->reject(DOMException::create(NotSupportedError));
             return promise;
@@ -110,7 +117,7 @@ ScriptPromise USB::requestDevice(ScriptState* scriptState, const USBDeviceReques
     }
 
     String errorMessage;
-    if (!scriptState->getExecutionContext()->isSecureContext(errorMessage)) {
+    if (!executionContext->isSecureContext(errorMessage)) {
         resolver->reject(DOMException::create(SecurityError, errorMessage));
     } else if (!UserGestureIndicator::consumeUserGesture()) {
         resolver->reject(DOMException::create(SecurityError, "Must be handling a user gesture to show a permission request."));