Add missing (and remove superfluous) 'explicit' from constructors.

content/browser/renderer_host/media/video_capture_host_unittest.cc

 // Copyright (c) 2012 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.
 
 #include <map>
 #include <string>
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 53 matching lines @@
     }
   }
 
  private:
   file_util::ScopedFILE file_;
   int expected_size_;
 };
 
 class MockVideoCaptureHost : public VideoCaptureHost {
  public:
-  MockVideoCaptureHost(MediaStreamManager* manager)
+  explicit MockVideoCaptureHost(MediaStreamManager* manager)
       : VideoCaptureHost(),
         return_buffers_(false),
         dump_video_(false),
         manager_(manager) {}
 
   // A list of mock methods.
   MOCK_METHOD4(OnNewBufferCreated,
                void(int device_id, base::SharedMemoryHandle handle,
                     int length, int buffer_id));
   MOCK_METHOD3(OnBufferFilled,
@@ skipping 292 matching lines @@
 #ifdef DUMP_VIDEO
 TEST_F(VideoCaptureHostTest, CaptureAndDumpVideoVga) {
   CaptureAndDumpVideo(640, 480, 30);
 }
 TEST_F(VideoCaptureHostTest, CaptureAndDump720P) {
   CaptureAndDumpVideo(1280, 720, 30);
 }
 #endif
 
 }  // namespace content