Use a mock implementation of Platform::crypto() for layout tests.

content/public/renderer/content_renderer_client.h

Index: content/public/renderer/content_renderer_client.h
diff --git a/content/public/renderer/content_renderer_client.h b/content/public/renderer/content_renderer_client.h
index 080d5ca983bb07adc39226cca6ce300321ba9774..e12d39bbdd0159e70d68ee84a293b264fd61de2b 100644
--- a/content/public/renderer/content_renderer_client.h
+++ b/content/public/renderer/content_renderer_client.h
@@ -28,6 +28,7 @@ class MessageLoop;
 namespace WebKit {
 class WebAudioDevice;
 class WebClipboard;
+class WebCrypto;
 class WebFrame;
 class WebHyphenator;
 class WebMIDIAccessor;
@@ -158,6 +159,10 @@ class CONTENT_EXPORT ContentRendererClient {
   virtual WebKit::WebSpeechSynthesizer* OverrideSpeechSynthesizer(
       WebKit::WebSpeechSynthesizerClient* client);
 
+  // Allows the embedder to override the WebCrypto used.
+  // If it returns NULL the content layer will handle crypto.
+  virtual WebKit::WebCrypto* OverrideWebCrypto();
+
   // Returns true if the renderer process should schedule the idle handler when
   // all widgets are hidden.
   virtual bool RunIdleHandlerWhenWidgetsHidden();