[sensors] Fix flakiness in generic sensors tests

third_party/WebKit/Source/modules/sensor/SensorProviderProxy.cpp

Index: third_party/WebKit/Source/modules/sensor/SensorProviderProxy.cpp
diff --git a/third_party/WebKit/Source/modules/sensor/SensorProviderProxy.cpp b/third_party/WebKit/Source/modules/sensor/SensorProviderProxy.cpp
index b2309114253196c350bd7826deba6e89434ab4e1..d6c5e6fe19f860b287c9a17e833d976099fe96eb 100644
--- a/third_party/WebKit/Source/modules/sensor/SensorProviderProxy.cpp
+++ b/third_party/WebKit/Source/modules/sensor/SensorProviderProxy.cpp
@@ -14,6 +14,12 @@ namespace blink {
 
 // SensorProviderProxy
 SensorProviderProxy::SensorProviderProxy(LocalFrame* frame) {
+  initialize(frame);
+}
+
+void SensorProviderProxy::initialize(LocalFrame* frame) {
+  DCHECK(!isInitialized());
+
   frame->interfaceProvider()->getInterface(mojo::GetProxy(&m_sensorProvider));
   m_sensorProvider.set_connection_error_handler(convertToBaseCallback(
       WTF::bind(&SensorProviderProxy::onSensorProviderConnectionError,
@@ -32,6 +38,10 @@ SensorProviderProxy* SensorProviderProxy::from(LocalFrame* frame) {
     result = new SensorProviderProxy(frame);
     Supplement<LocalFrame>::provideTo(*frame, supplementName(), result);
   }
+
+  if (!result->isInitialized())
+    result->initialize(frame);
+
   return result;
 }