Verify promise type before casting.

media/base/cdm_promise.h

Index: media/base/cdm_promise.h
diff --git a/media/base/cdm_promise.h b/media/base/cdm_promise.h
index 14f79f852d149a4a80471e823c873508ec10d8fc..2799f134fe73428a67642a23ee0f8b0e5262dc78 100644
--- a/media/base/cdm_promise.h
+++ b/media/base/cdm_promise.h
@@ -35,6 +35,12 @@ class MEDIA_EXPORT CdmPromise {
     NUM_RESULT_CODES
   };
 
+  enum ResolveParameterType {
+    VOID_TYPE,
+    STRING_TYPE,
+    KEY_IDS_VECTOR_TYPE,

[xhwang, 2014/08/27 22:49:26]

nit: no trailing comma to be consistent

[jrummell, 2014/08/27 23:05:13]

Done. The enum above has NUM_RESULT_CODES as always the last enum, where here
the list may grow if we add new templated versions.

+  };
+
   typedef base::Callback<void(MediaKeys::Exception exception_code,
                               uint32 system_code,
                               const std::string& error_message)>
@@ -50,6 +56,8 @@ class MEDIA_EXPORT CdmPromise {
                       uint32 system_code,
                       const std::string& error_message);
 
+  virtual ResolveParameterType GetResolveParameterType() const = 0;
+
  protected:
   CdmPromise();
   CdmPromise(PromiseRejectedCB reject_cb);
@@ -80,6 +88,7 @@ class MEDIA_EXPORT CdmPromiseTemplate : public CdmPromise {
                      const std::string& uma_name);
   virtual ~CdmPromiseTemplate();
   virtual void resolve(const T& result);
+  virtual ResolveParameterType GetResolveParameterType() const OVERRIDE;
 
  protected:
   // Allow subclasses to completely override the implementation.
@@ -104,6 +113,7 @@ class MEDIA_EXPORT CdmPromiseTemplate<void> : public CdmPromise {
                      const std::string& uma_name);
   virtual ~CdmPromiseTemplate();
   virtual void resolve();
+  virtual ResolveParameterType GetResolveParameterType() const OVERRIDE;
 
  protected:
   // Allow subclasses to completely override the implementation.