Expose WebCrypto's lookupAlgorithmInfo.

public/platform/WebCryptoAlgorithm.h

Index: public/platform/WebCryptoAlgorithm.h
diff --git a/public/platform/WebCryptoAlgorithm.h b/public/platform/WebCryptoAlgorithm.h
index 0a8e9b49c2d67ad6b5008af39e38771e1239afee..09896b44f6b871775ee3bc0dd0b3257458f0d754 100644
--- a/public/platform/WebCryptoAlgorithm.h
+++ b/public/platform/WebCryptoAlgorithm.h
@@ -85,6 +85,20 @@ enum WebCryptoAlgorithmParamsType {
     WebCryptoAlgorithmParamsTypeAesCtrParams,
 };
 
+struct WebCryptoAlgorithmInfo {
+    typedef char ParamsTypeOrUndefined;
+    static const ParamsTypeOrUndefined Undefined = -1;
+
+    // The canonical (case-sensitive) name for the algorithm as a
+    // null-terminated C-string literal.
+    const char* name;
+
+    // A map from the operation to the expected parameter type of the algorithm.
+    // If an operation is not applicable for the algorithm, set to Undefined.
+    const ParamsTypeOrUndefined operationToParamsType[WebCryptoOperationLast + 1];
+};
+
+
 class WebCryptoAesCbcParams;
 class WebCryptoAesKeyGenParams;
 class WebCryptoHmacImportParams;
@@ -115,6 +129,11 @@ public:
     BLINK_PLATFORM_EXPORT static WebCryptoAlgorithm createNull();
     BLINK_PLATFORM_EXPORT static WebCryptoAlgorithm adoptParamsAndCreate(WebCryptoAlgorithmId, WebCryptoAlgorithmParams*);
 
+    // Returns a WebCryptoAlgorithmInfo for the algorithm with the given ID. If
+    // the ID is invalid, return 0. The caller can assume the pointer will be
+    // valid for the program's entire runtime.
+    BLINK_PLATFORM_EXPORT static const WebCryptoAlgorithmInfo* lookupAlgorithmInfo(WebCryptoAlgorithmId);
+
     ~WebCryptoAlgorithm() { reset(); }
 
     WebCryptoAlgorithm(const WebCryptoAlgorithm& other) { assign(other); }