Fix IDL dependency computation for partial interfaces

Source/bindings/scripts/generate_bindings.pl

 #!/usr/bin/perl -w
 #
 # Copyright (C) 2005 Apple Computer, Inc.
 # Copyright (C) 2006 Anders Carlsson <andersca@mac.com>
 #
 # This file is part of WebKit
 #
 # This library is free software; you can redistribute it and/or
 # modify it under the terms of the GNU Library General Public
 # License as published by the Free Software Foundation; either
@@ skipping 70 matching lines @@
         my ($idlFile, @followingIdlFiles) = split(/\s+/, $line);
         if ($idlFile and basename($idlFile) eq basename($targetIdlFile)) {
             $idlFound = 1;
             # We sort the dependency IDL files so that the corresponding code is generated
             # in a consistent order. This is important for the bindings tests.
             @dependencyIdlFiles = sort @followingIdlFiles;
         }
     }
     close FH;
 
-    # $additionalIdlFiles is list of IDL files which should not be included in
-    # DerivedSources*.cpp (i.e. they are not described in the interface
-    # dependencies file) but should generate .h and .cpp files.
+    # $additionalIdlFiles is for IDL files not listed in the interface
+    # dependencies file, namely generated IDL files for interfaces
+    # (not partial interfaces), so we need to generate .h and .cpp files.
     if (!$idlFound and $additionalIdlFiles) {
         my @idlFiles = shellwords($additionalIdlFiles);
         $idlFound = grep { $_ and basename($_) eq basename($targetIdlFile) } @idlFiles;
     }
 
     if (!$idlFound) {
-        # We generate empty .h and .cpp files just to tell build scripts that .h and .cpp files are created.
+        # IDL files for dependencies (partial interfaces and interfaces
+        # implemented elsewhere). We generate empty .h and .cpp files just to
+        # tell build scripts that outputs have been created.
         generateEmptyHeaderAndCpp($targetInterfaceName, $outputDirectory);
         exit 0;
     }
 }
 
 # Parse the target IDL file.
 my $targetParser = idl_parser->new(!$verbose);
 my $targetDocument = $targetParser->Parse($targetIdlFile, $preprocessor);
 
 if ($idlAttributesFile) {
@@ skipping 184 matching lines @@
                 last OUTER;
             }
         }
     }
     if ($error) {
         die "IDL ATTRIBUTE CHECKER ERROR: $error
 If you want to add a new IDL attribute, you need to add it to bindings/scripts/IDLAttributes.txt and add explanations to the Blink IDL document (http://chromium.org/blink/webidl).
 ";
     }
 }