[ChromeDriver] Adjust DevTools connection retry

Adjust when to retry while connecting to DevTools. The retry timeout
now starts at 1 second, with exponential backoff, up to 16 seconds.

Bug: 826150
Change-Id: Ia8dfdd27ab88ac6f466555a943810242188604d6
Reviewed-on: https://chromium-review.googlesource.com/1034385Reviewed-by: Jonathon Kereliuk <kereliuk@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#554766}

chrome/test/chromedriver/net/sync_websocket_impl.cc

@@ -55,16 +55,18 @@ bool SyncWebSocketImpl::Core::Connect(const GURL& url) {
   bool success = false;
   base::WaitableEvent event(base::WaitableEvent::ResetPolicy::AUTOMATIC,
                             base::WaitableEvent::InitialState::NOT_SIGNALED);
-  // Try to connect up to 3 times, with 10 seconds delay in between.
-  base::TimeDelta waitTime = base::TimeDelta::FromSeconds(10);
-  for (int i = 0; i < 3; i++) {
+  // Connect with retries. The retry timeout starts at 1 second, with
+  // exponential backoff, up to 16 seconds. The maximum total wait time is
+  // about 31 seconds.
+  const int kMaxTimeout = 16;
+  for (int timeout = 1; timeout <= kMaxTimeout; timeout *= 2) {
     context_getter_->GetNetworkTaskRunner()->PostTask(
         FROM_HERE, base::BindOnce(&SyncWebSocketImpl::Core::ConnectOnIO, this,
                                   url, &success, &event));
-    if (event.TimedWait(waitTime))
+    if (event.TimedWait(base::TimeDelta::FromSeconds(timeout)))
       break;
     LOG(WARNING) << "Timed out connecting to Chrome, "
-                 << (i < 2 ? "retrying..." : "giving up.");
+                 << (timeout < kMaxTimeout ? "retrying..." : "giving up.");
   }
   return success;
 }