Added device count test.

chrome/browser/devtools/device/devtools_android_bridge.cc

Index: chrome/browser/devtools/device/devtools_android_bridge.cc
diff --git a/chrome/browser/devtools/device/devtools_android_bridge.cc b/chrome/browser/devtools/device/devtools_android_bridge.cc
index 5fefecc91fd06be14e3a306811c07f953321afba..9cb0e21ebe3932b6175902396f7391b17a227bc2 100644
--- a/chrome/browser/devtools/device/devtools_android_bridge.cc
+++ b/chrome/browser/devtools/device/devtools_android_bridge.cc
@@ -1198,7 +1198,8 @@ DevToolsAndroidBridge::HandlerThread::~HandlerThread() {
 
 DevToolsAndroidBridge::DevToolsAndroidBridge(Profile* profile)
     : profile_(profile),
-      handler_thread_(HandlerThread::GetInstance()) {
+      handler_thread_(HandlerThread::GetInstance()),
+      polling_interval_for_test_(0) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   pref_change_registrar_.Init(profile_->GetPrefs());
   pref_change_registrar_.Add(prefs::kDevToolsDiscoverUsbDevicesEnabled,
@@ -1305,7 +1306,9 @@ void DevToolsAndroidBridge::ReceivedDeviceList(RemoteDevices* devices_ptr) {
       BrowserThread::UI,
       FROM_HERE,
       base::Bind(&DevToolsAndroidBridge::RequestDeviceList, this),
-      base::TimeDelta::FromMilliseconds(kAdbPollingIntervalMs));
+      base::TimeDelta::FromMilliseconds(polling_interval_for_test_
+                                            ? polling_interval_for_test_
+                                            : kAdbPollingIntervalMs));
 }
 
 void DevToolsAndroidBridge::RequestDeviceCount() {
@@ -1333,7 +1336,9 @@ void DevToolsAndroidBridge::ReceivedDeviceCount(int count) {
       BrowserThread::UI,
       FROM_HERE,
       base::Bind(&DevToolsAndroidBridge::RequestDeviceCount, this),
-      base::TimeDelta::FromMilliseconds(kAdbPollingIntervalMs));
+      base::TimeDelta::FromMilliseconds(polling_interval_for_test_
+                                            ? polling_interval_for_test_
+                                            : kAdbPollingIntervalMs));
 }
 
 void DevToolsAndroidBridge::CreateDeviceProviders() {