[webcrypto] Fix a race in BlinkPlatformImpl::crypto(), by using eager initilization of WebCryptoImpl

content/child/webcrypto/webcrypto_impl.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_IMPL_H_
 #define CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "third_party/WebKit/public/platform/WebCrypto.h"
 #include "third_party/WebKit/public/platform/WebCryptoAlgorithm.h"
 #include "third_party/WebKit/public/platform/WebVector.h"
 
 namespace content {
 
 // Wrapper around the Blink WebCrypto asynchronous interface, which forwards to
-// the synchronous platfrom (NSS or OpenSSL) implementation.
+// the synchronous platform (NSS or OpenSSL) implementation.
 //
-// TODO(eroman): Post the synchronous work to a background thread.
+// WebCryptoImpl is threadsafe.
+//
+// EnsureInit() must be called prior to using methods on WebCryptoImpl().
 class WebCryptoImpl : public blink::WebCrypto {
  public:
   WebCryptoImpl();
+
   virtual ~WebCryptoImpl();
 
+  static void EnsureInit();
+
   virtual void encrypt(const blink::WebCryptoAlgorithm& algorithm,
                        const blink::WebCryptoKey& key,
                        const unsigned char* data,
                        unsigned int data_size,
                        blink::WebCryptoResult result);
   virtual void decrypt(const blink::WebCryptoAlgorithm& algorithm,
                        const blink::WebCryptoKey& key,
                        const unsigned char* data,
                        unsigned int data_size,
                        blink::WebCryptoResult result);
@@ skipping 64 matching lines @@
   virtual bool serializeKeyForClone(const blink::WebCryptoKey& key,
                                     blink::WebVector<unsigned char>& key_data);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WebCryptoImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_IMPL_H_