Try to cut down Browser/TabContents header dependencies.

chrome/common/page_transition_types.h

 // Copyright (c) 2010 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 CHROME_COMMON_PAGE_TRANSITION_TYPES_H__
 #define CHROME_COMMON_PAGE_TRANSITION_TYPES_H__
 
 #include "base/basictypes.h"
-#include "base/logging.h"
 
 // This class is for scoping only.
 class PageTransition {
  public:
   // Types of transitions between pages. These are stored in the history
   // database to separate visits, and are reported by the renderer for page
   // navigations.
   //
   // WARNING: don't change these numbers. They are written directly into the
   // history database, so future versions will need the same values to match
@@ skipping 104 matching lines @@
   };
 
   // The type used for the bitfield.
   typedef unsigned int Type;
 
   static bool ValidType(int32 type) {
     Type t = StripQualifier(static_cast<Type>(type));
     return (t <= LAST_CORE);
   }
 
-  static Type FromInt(int32 type) {
-    if (!ValidType(type)) {
-      NOTREACHED() << "Invalid transition type " << type;
-
-      // Return a safe default so we don't have corrupt data in release mode.
-      return LINK;
-    }
-    return static_cast<Type>(type);
-  }
+  static Type FromInt(int32 type);
 
   // Returns true if the given transition is a top-level frame transition, or
   // false if the transition was for a subframe.
   static bool IsMainFrame(Type type) {
     int32 t = StripQualifier(type);
     return (t != AUTO_SUBFRAME && t != MANUAL_SUBFRAME);
   }
 
   // Returns whether a transition involves a redirection
   static bool IsRedirect(Type type) {
     return (type & IS_REDIRECT_MASK) != 0;
   }
 
   // Simplifies the provided transition by removing any qualifier
   static Type StripQualifier(Type type) {
     return static_cast<Type>(type & ~QUALIFIER_MASK);
   }
 
   // Return the qualifier
   static int32 GetQualifier(Type type) {
     return type & QUALIFIER_MASK;
   }
 
   // Return a string version of the core type values.
   static const char* CoreTransitionString(Type type);
 };
 
 #endif  // CHROME_COMMON_PAGE_TRANSITION_TYPES_H__