media: Add KeySystems::CanUseAesDecryptor()

This allows KeySystemConfigSelectorTest to fully depend on the
FakeKeySystems. Previously KeySystemConfigSelector calls
CanUseAesDecryptor() which calls into KeySystemsImpl which makes the
test really confusing.

Bug: 727948
Change-Id: Id5536a142285034f1ec589758a171c70d3a77153
Reviewed-on: https://chromium-review.googlesource.com/1092412Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565716}

media/base/key_systems.cc

@@ -200,8 +200,6 @@ class KeySystemsImpl : public KeySystems {
 
   std::string GetKeySystemNameForUMA(const std::string& key_system) const;
 
-  bool UseAesDecryptor(const std::string& key_system) const;
-
   // These two functions are for testing purpose only.
   void AddCodecMask(EmeMediaType media_type,
                     const std::string& codec,
@@ -211,6 +209,8 @@ class KeySystemsImpl : public KeySystems {
   // Implementation of KeySystems interface.
   bool IsSupportedKeySystem(const std::string& key_system) const override;
 
+  bool CanUseAesDecryptor(const std::string& key_system) const override;
+
   bool IsSupportedInitDataType(const std::string& key_system,
                                EmeInitDataType init_data_type) const override;
 
@@ -531,18 +531,6 @@ std::string KeySystemsImpl::GetKeySystemNameForUMA(
   return kUnknownKeySystemNameForUMA;
 }
 
-bool KeySystemsImpl::UseAesDecryptor(const std::string& key_system) const {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  KeySystemPropertiesMap::const_iterator key_system_iter =
-      key_system_properties_map_.find(key_system);
-  if (key_system_iter == key_system_properties_map_.end()) {
-    DLOG(ERROR) << key_system << " is not a known key system";
-    return false;
-  }
-  return key_system_iter->second->UseAesDecryptor();
-}
-
 void KeySystemsImpl::AddCodecMask(EmeMediaType media_type,
                                   const std::string& codec,
                                   uint32_t mask) {
@@ -570,6 +558,18 @@ bool KeySystemsImpl::IsSupportedKeySystem(const std::string& key_system) const {
   return true;
 }
 
+bool KeySystemsImpl::CanUseAesDecryptor(const std::string& key_system) const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  KeySystemPropertiesMap::const_iterator key_system_iter =
+      key_system_properties_map_.find(key_system);
+  if (key_system_iter == key_system_properties_map_.end()) {
+    DLOG(ERROR) << key_system << " is not a known key system";
+    return false;
+  }
+  return key_system_iter->second->UseAesDecryptor();
+}
+
 EmeConfigRule KeySystemsImpl::GetContentTypeConfigRule(
     const std::string& key_system,
     EmeMediaType media_type,
@@ -727,7 +727,7 @@ std::string GetKeySystemNameForUMA(const std::string& key_system) {
 }
 
 bool CanUseAesDecryptor(const std::string& key_system) {
-  return KeySystemsImpl::GetInstance()->UseAesDecryptor(key_system);
+  return KeySystemsImpl::GetInstance()->CanUseAesDecryptor(key_system);
 }
 
 // These two functions are for testing purpose only. The declaration in the

media/base/key_systems.h

@@ -31,6 +31,9 @@ class MEDIA_EXPORT KeySystems {
   // Returns whether |key_system| is a supported key system.
   virtual bool IsSupportedKeySystem(const std::string& key_system) const = 0;
 
+  // Returns whether AesDecryptor can be used for the given |key_system|.
+  virtual bool CanUseAesDecryptor(const std::string& key_system) const = 0;
+
   // Returns whether |init_data_type| is supported by |key_system|.
   virtual bool IsSupportedInitDataType(
       const std::string& key_system,

media/blink/key_system_config_selector.cc

@@ -337,8 +337,9 @@ bool KeySystemConfigSelector::IsSupportedContentType(
   // is done primarily to validate extended codecs, but it also ensures that the
   // CDM cannot support codecs that Chrome does not (which could complicate the
   // robustness algorithm).
-  if (!is_supported_media_type_cb_.Run(container_lower, codecs,
-                                       CanUseAesDecryptor(key_system))) {
+  if (!is_supported_media_type_cb_.Run(
+          container_lower, codecs,
+          key_systems_->CanUseAesDecryptor(key_system))) {
     DVLOG(3) << "Container mime type and codecs are not supported";
     return false;
   }

media/blink/key_system_config_selector_unittest.cc

@@ -158,9 +158,12 @@ class FakeKeySystems : public KeySystems {
 
   bool IsSupportedKeySystem(const std::string& key_system) const override {
     // Based on EME spec, Clear Key key system is always supported.
-    if (key_system == kSupportedKeySystem || key_system == kClearKeyKeySystem)
-      return true;
-    return false;
+    return key_system == kSupportedKeySystem ||
+           key_system == kClearKeyKeySystem;
+  }
+
+  bool CanUseAesDecryptor(const std::string& key_system) const override {
+    return key_system == kClearKeyKeySystem;
   }
 
   // TODO(sandersd): Move implementation into KeySystemConfigSelector?