Add throttling to corrupt policy extensions reinstall

chrome/browser/extensions/chrome_content_verifier_delegate.h

Index: chrome/browser/extensions/chrome_content_verifier_delegate.h
diff --git a/chrome/browser/extensions/chrome_content_verifier_delegate.h b/chrome/browser/extensions/chrome_content_verifier_delegate.h
index f889170e944d17dc1aac17d025e4f154aa9bcf2d..1d7e21808885e6fb28e9d8735cd81d90614be34a 100644
--- a/chrome/browser/extensions/chrome_content_verifier_delegate.h
+++ b/chrome/browser/extensions/chrome_content_verifier_delegate.h
@@ -5,9 +5,12 @@
 #ifndef CHROME_BROWSER_EXTENSIONS_CHROME_CONTENT_VERIFIER_DELEGATE_H_
 #define CHROME_BROWSER_EXTENSIONS_CHROME_CONTENT_VERIFIER_DELEGATE_H_
 
+#include <map>
+#include <memory>
 #include <set>
 #include <string>
 
+#include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "extensions/browser/content_verifier_delegate.h"
 
@@ -15,6 +18,10 @@ namespace content {
 class BrowserContext;
 }
 
+namespace net {
+class BackoffEntry;
+}
+
 namespace extensions {
 
 class ChromeContentVerifierDelegate : public ContentVerifierDelegate {
@@ -35,10 +42,23 @@ class ChromeContentVerifierDelegate : public ContentVerifierDelegate {
   void VerifyFailed(const std::string& extension_id,
                     ContentVerifyJob::FailureReason reason) override;
 
+ protected:
+  FRIEND_TEST_ALL_PREFIXES(ContentVerifierPolicyTest, Backoff);
+  // For tests, overrides the default action to take to initiate policy
+  // force-reinstalls.
+  static void set_policy_reinstall_action_for_test(
+      base::Callback<void(base::TimeDelta delay)> action);
+
  private:
   content::BrowserContext* context_;
   ContentVerifierDelegate::Mode default_mode_;
 
+  // This maps an extension id to a backoff entry for slowing down
+  // redownload/reinstall of corrupt policy extensions if it keeps happening
+  // in a loop (eg crbug.com/661738).
+  std::map<std::string, std::unique_ptr<net::BackoffEntry>>
+      policy_reinstall_backoff_;
+
   // For reporting metrics in BOOTSTRAP mode, when an extension would be
   // disabled if content verification was in ENFORCE mode.
   std::set<std::string> would_be_disabled_ids_;