Fix shared libary build for content_browsertests.

Source/web/WebMIDIClientMock.cpp

Index: Source/web/WebMIDIClientMock.cpp
diff --git a/Source/web/WebMIDIClientMock.cpp b/Source/web/WebMIDIClientMock.cpp
index 309dcee4e9989690d05ceb44f2050a002975502c..4aa31ec28ff8874dbc73ca38598dc60ff6e04d38 100644
--- a/Source/web/WebMIDIClientMock.cpp
+++ b/Source/web/WebMIDIClientMock.cpp
@@ -42,6 +42,11 @@ WebMIDIClientMock::WebMIDIClientMock()
     m_clientMock.reset(new MIDIClientMock());
 }
 
+WebMIDIClientMock::~WebMIDIClientMock()
+{
+    m_clientMock.reset(0);
+}
+
 void WebMIDIClientMock::setSysexPermission(bool allowed)
 {
     m_clientMock->setSysexPermission(allowed);
@@ -62,9 +67,4 @@ void WebMIDIClientMock::cancelSysexPermissionRequest(const WebMIDIPermissionRequ
     m_clientMock->cancelSysexPermissionRequest(request.midiAccessInitializer());
 }
 
-void WebMIDIClientMock::reset()
-{
-    m_clientMock.reset(0);
-}
-
 } // namespace blink