Try 2: Completely redo how themes are stored on disk and processed at install time.

chrome/browser/browser_theme_provider_mac.mm

 // Copyright (c) 2009 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.
 
 #include "chrome/browser/browser_theme_provider.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "app/gfx/color_utils.h"
 #include "base/logging.h"
+#include "chrome/browser/browser_theme_pack.h"
 #include "skia/ext/skia_utils_mac.h"
 
 namespace {
 
 void HSLToHSB(const color_utils::HSL& hsl, CGFloat* h, CGFloat* s, CGFloat* b) {
   SkColor color = color_utils::HSLToSkColor(hsl, 255);  // alpha doesn't matter
   SkScalar hsv[3];
   SkColorToHSV(color, hsv);
 
   *h = SkScalarToDouble(hsv[0]) / 360.0;
@@ skipping 47 matching lines @@
 }
 
 NSColor* BrowserThemeProvider::GetNSColor(int id) const {
   DCHECK(CalledOnValidThread());
 
   // Check to see if we already have the color in the cache.
   NSColorMap::const_iterator nscolor_iter = nscolor_cache_.find(id);
   if (nscolor_iter != nscolor_cache_.end())
     return nscolor_iter->second;
 
-  ColorMap::const_iterator color_iter = colors_.find(GetColorKey(id));
-  if (color_iter != colors_.end()) {
-    const SkColor& sk_color = color_iter->second;
+  SkColor sk_color;
+  if (theme_pack_.get() && theme_pack_->GetColor(id, &sk_color)) {
     NSColor* color = [NSColor
         colorWithCalibratedRed:SkColorGetR(sk_color)/255.0
                          green:SkColorGetG(sk_color)/255.0
                           blue:SkColorGetB(sk_color)/255.0
                          alpha:SkColorGetA(sk_color)/255.0];
 
     // We loaded successfully.  Cache the color.
     if (color) {
       nscolor_cache_[id] = [color retain];
       return color;
     }
   }
 
   return nil;
 }
 
 NSColor* BrowserThemeProvider::GetNSColorTint(int id) const {
   DCHECK(CalledOnValidThread());
 
   // Check to see if we already have the color in the cache.
   NSColorMap::const_iterator nscolor_iter = nscolor_cache_.find(id);
   if (nscolor_iter != nscolor_cache_.end())
     return nscolor_iter->second;
 
-  TintMap::const_iterator tint_iter = tints_.find(GetTintKey(id));
-  if (tint_iter != tints_.end()) {
-    color_utils::HSL tint = tint_iter->second;
+  color_utils::HSL tint;
+  if (theme_pack_.get() && theme_pack_->GetTint(id, &tint)) {
     CGFloat hue, saturation, brightness;
     HSLToHSB(tint, &hue, &saturation, &brightness);
 
     NSColor* tint_color = [NSColor colorWithCalibratedHue:hue
                                                saturation:saturation
                                                brightness:brightness
                                                     alpha:1.0];
 
     // We loaded successfully.  Cache the color.
     if (tint_color) {
@@ skipping 15 matching lines @@
   }
   nsimage_cache_.clear();
 
   // Free colors.
   for (NSColorMap::iterator i = nscolor_cache_.begin();
        i != nscolor_cache_.end(); i++) {
     [i->second release];
   }
   nscolor_cache_.clear();
 }