media: Reject pending CDM promise during destruction.

third_party/WebKit/public/platform/WebContentDecryptionModuleResult.h

Index: third_party/WebKit/public/platform/WebContentDecryptionModuleResult.h
diff --git a/third_party/WebKit/public/platform/WebContentDecryptionModuleResult.h b/third_party/WebKit/public/platform/WebContentDecryptionModuleResult.h
index 9d16de997517112ef96501044288607c8f9e779e..6c5e111583a7ecb1eabea681c424c7c4766d4b3b 100644
--- a/third_party/WebKit/public/platform/WebContentDecryptionModuleResult.h
+++ b/third_party/WebKit/public/platform/WebContentDecryptionModuleResult.h
@@ -45,6 +45,9 @@ public:
         return *this;
     }
 
+    // Returns whether the operation has been completed (success or fail).
+    BLINK_PLATFORM_EXPORT bool isCompleted();
+
     // Called when the CDM completes an operation and has no additional data to
     // pass back.
     BLINK_PLATFORM_EXPORT void complete();