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

cc/managed_memory_policy.h

 // Copyright 2011 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 CC_MANAGED_MEMORY_POLICY_H_
 #define CC_MANAGED_MEMORY_POLICY_H_
 
 #include "base/basictypes.h"
 #include "cc/cc_export.h"
 #include "cc/tile_priority.h"
 
 namespace cc {
 
 struct CC_EXPORT ManagedMemoryPolicy {
      enum PriorityCutoff {
         CUTOFF_ALLOW_NOTHING,
         CUTOFF_ALLOW_REQUIRED_ONLY,
         CUTOFF_ALLOW_NICE_TO_HAVE,
         CUTOFF_ALLOW_EVERYTHING,
     };
 
-    ManagedMemoryPolicy(size_t bytesLimitWhenVisible);
+    explicit ManagedMemoryPolicy(size_t bytesLimitWhenVisible);
     ManagedMemoryPolicy(size_t bytesLimitWhenVisible,
                         PriorityCutoff priorityCutoffWhenVisible,
                         size_t bytesLimitWhenNotVisible,
                         PriorityCutoff priorityCutoffWhenNotVisible);
     bool operator==(const ManagedMemoryPolicy&) const;
     bool operator!=(const ManagedMemoryPolicy&) const;
 
     size_t bytesLimitWhenVisible;
     PriorityCutoff priorityCutoffWhenVisible;
     size_t bytesLimitWhenNotVisible;
     PriorityCutoff priorityCutoffWhenNotVisible;
 
     static int priorityCutoffToValue(PriorityCutoff priorityCutoff);
     static TileMemoryLimitPolicy priorityCutoffToTileMemoryLimitPolicy(PriorityCutoff priorityCutoff);
 };
 
 }  // namespace cc
 
 #endif  // CC_MANAGED_MEMORY_POLICY_H_