Use PL_strncpyz in DR_FrameTypeInfo. (Bug 639220) r=dbaron

layout/generic/nsFrame.cpp

@@ -7601,8 +7601,8 @@ DR_FrameTypeInfo::DR_FrameTypeInfo(nsIAtom* aFrameType,
                                    const char* aFrameName)
 {
   mType = aFrameType;
-  strcpy(mNameAbbrev, aFrameNameAbbrev);
-  strcpy(mName, aFrameName);
+  PL_strncpyz(mNameAbbrev, aFrameNameAbbrev, sizeof(mNameAbbrev));
+  PL_strncpyz(mName, aFrameName, sizeof(mName));
 }
 
 struct DR_FrameTreeNode