media: Reject pending CDM promise during destruction.

There are legit cases where a CDM promise could be destructed before
it's fulfilled. For example, a promise could be bound into a callback
and the callback is dropped.

BUG=585356

Review URL: https://codereview.chromium.org/1729063003

Cr-Commit-Position: refs/heads/master@{#378588}

1 files changed, 7 insertions, 2 deletions

diff --git a/chromecast/media/cdm/browser_cdm_cast.cc b/chromecast/media/cdm/browser_cdm_cast.cc
index 380c362..e5585c5 100644
--- a/chromecast/media/cdm/browser_cdm_cast.cc
+++ b/chromecast/media/cdm/browser_cdm_cast.cc
@@ -29,8 +29,11 @@ class CdmPromiseInternal : public ::media::CdmPromiseTemplate<T...> {
         promise_(std::move(promise)) {}
 
   ~CdmPromiseInternal() final {
-    // Promise must be resolved or rejected before destruction.
-    DCHECK(!promise_);
+    if (IsPromiseSettled())
+      return;
+
+    DCHECK(promise_);
+    RejectPromiseOnDestruction();
   }
 
   // CdmPromiseTemplate<> implementation.
@@ -48,7 +51,9 @@ class CdmPromiseInternal : public ::media::CdmPromiseTemplate<T...> {
   }
 
  private:
+  using ::media::CdmPromiseTemplate<T...>::IsPromiseSettled;
   using ::media::CdmPromiseTemplate<T...>::MarkPromiseSettled;
+  using ::media::CdmPromiseTemplate<T...>::RejectPromiseOnDestruction;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   scoped_ptr<::media::CdmPromiseTemplate<T...>> promise_;