Use an exponential timeout falloff for translate CLD requests

The TranslateHelper kicks off a (potentially non-termiting) series of
requests for CLD data until it gets a valid response. As there are
(currently) no guarantees that a valid response will be received,
change the repeat timeout from a fixed 1s delay to a delay that decays
gracefully over time.

BUG=437869

Review URL: https://codereview.chromium.org/793643004

Cr-Commit-Position: refs/heads/master@{#308799}

1 files changed, 11 insertions, 1 deletions

diff --git a/components/translate/content/renderer/translate_helper.cc b/components/translate/content/renderer/translate_helper.cc
index 83d9bc3..aa67a6a 100644
--- a/components/translate/content/renderer/translate_helper.cc
+++ b/components/translate/content/renderer/translate_helper.cc
@@ -577,6 +577,9 @@ void TranslateHelper::CancelCldDataPolling() {
 
 void TranslateHelper::SendCldDataRequest(const int delay_millis,
                                          const int next_delay_millis) {
+  DCHECK_GE(delay_millis, 0);
+  DCHECK_GT(next_delay_millis, 0);
+
   // Terminate immediately if told to stop polling.
   if (cld_data_polling_canceled_) {
     DVLOG(1) << "Aborting CLD data request (polling canceled)";
@@ -589,6 +592,13 @@ void TranslateHelper::SendCldDataRequest(const int delay_millis,
     return;
   }
 
+  // Terminate immediately if the decayed delay is sufficiently large.
+  if (next_delay_millis > std::numeric_limits<int>::max() / 2) {
+    DVLOG(1) << "Aborting CLD data request (exceeded max number of requests)";
+    cld_data_polling_started_ = false;
+    return;
+  }
+
   if (!g_cld_callback_set) {
     g_cld_callback_set = true;
     cld_data_provider_->SetCldAvailableCallback(
@@ -613,7 +623,7 @@ void TranslateHelper::SendCldDataRequest(const int delay_millis,
       base::Bind(&TranslateHelper::SendCldDataRequest,
                  weak_method_factory_.GetWeakPtr(),
                  next_delay_millis,
-                 next_delay_millis),
+                 next_delay_millis * 2),
       base::TimeDelta::FromMilliseconds(delay_millis));
 }