r169 provides a 25% performance improvement in the Xcode generator.  Profiling indicated that PBXGroup.AddOrGetFileByPath was a major hotspot.  A dict is added to that class to track child objects by path rather than performing a linear search through all children.
r169 provides a 25% performance improvement in the Xcode generator.  Profiling
indicated that PBXGroup.AddOrGetFileByPath was a major hotspot.  A dict is
added to that class to track child objects by path rather than performing a
linear search through all children.

witwall/gyp,witwall/gyp,witwall/gyp,witwall/gyp,witwall/gyp