Encrypted Media: Handle blink::WebString in WebMediaPlayer*.

content/renderer/media/android/webmediaplayer_android.h

Index: content/renderer/media/android/webmediaplayer_android.h
diff --git a/content/renderer/media/android/webmediaplayer_android.h b/content/renderer/media/android/webmediaplayer_android.h
index 1012d684c4d25f0523177ff8097ac2da85893d1b..318463c50c2a36ff48e7341f08503a629082c226 100644
--- a/content/renderer/media/android/webmediaplayer_android.h
+++ b/content/renderer/media/android/webmediaplayer_android.h
@@ -264,23 +264,23 @@ class WebMediaPlayerAndroid
   void DidLoadMediaInfo(MediaInfoLoader::Status status);
   void DoReleaseRemotePlaybackTexture(uint32 sync_point);
 
-  bool IsKeySystemSupported(const blink::WebString& key_system);
+  bool IsKeySystemSupported(const std::string& key_system);
 
   // Actually do the work for generateKeyRequest/addKey so they can easily
   // report results to UMA.
   MediaKeyException GenerateKeyRequestInternal(
-      const blink::WebString& key_system,
+      const std::string& key_system,
       const unsigned char* init_data,
       unsigned init_data_length);
-  MediaKeyException AddKeyInternal(const blink::WebString& key_system,
+  MediaKeyException AddKeyInternal(const std::string& key_system,
                                    const unsigned char* key,
                                    unsigned key_length,
                                    const unsigned char* init_data,
                                    unsigned init_data_length,
-                                   const blink::WebString& session_id);
+                                   const std::string& session_id);
   MediaKeyException CancelKeyRequestInternal(
-      const blink::WebString& key_system,
-      const blink::WebString& session_id);
+      const std::string& key_system,
+      const std::string& session_id);
 
   // Requests that this object notifies when a decryptor is ready through the
   // |decryptor_ready_cb| provided.
@@ -433,7 +433,7 @@ class WebMediaPlayerAndroid
 
   // The currently selected key system. Empty string means that no key system
   // has been selected.
-  blink::WebString current_key_system_;
+  std::string current_key_system_;
 
   // Temporary for EME v0.1. In the future the init data type should be passed
   // through GenerateKeyRequest() directly from WebKit.