Add target_arch config variable to .isolate files.

chrome/chrome.isolate

Index: chrome/chrome.isolate
diff --git a/chrome/chrome.isolate b/chrome/chrome.isolate
index 37c934750c3f8051c8f87d1f475dc163a7113004..f03f3e31a9e0ab9bdbb70a4edc1d9c7f0d59fa21 100644
--- a/chrome/chrome.isolate
+++ b/chrome/chrome.isolate
@@ -60,11 +60,8 @@
           '<(PRODUCT_DIR)/<(version_full).manifest',
           '<(PRODUCT_DIR)/chrome.dll',
           '<(PRODUCT_DIR)/chrome_elf.dll',
-          '<(PRODUCT_DIR)/d3dcompiler_46.dll',
           '<(PRODUCT_DIR)/ffmpegsumo.dll',
-          '<(PRODUCT_DIR)/libEGL.dll',
           '<(PRODUCT_DIR)/libexif.dll',
-          '<(PRODUCT_DIR)/libGLESv2.dll',
           '<(PRODUCT_DIR)/nacl64<(EXECUTABLE_SUFFIX)',
           '<(PRODUCT_DIR)/osmesa.dll',
           '<(PRODUCT_DIR)/ppGoogleNaClPluginChrome.dll',
@@ -80,6 +77,6 @@
     }],
   ],
   'includes': [
-    '../base/base.isolate',
+    'angle.isolate',
   ],
 }