Make isolate_driver.py only add .dll/.so/.dylib for component builds' generated files.

tools/isolate_driver.py

Index: tools/isolate_driver.py
diff --git a/tools/isolate_driver.py b/tools/isolate_driver.py
index 40f0c6dbb944c114eb4a7600198a597281762ad1..f8602fbfb609eeac9cb2908092acd885b201767f 100755
--- a/tools/isolate_driver.py
+++ b/tools/isolate_driver.py
@@ -177,6 +177,12 @@ def post_process_deps(build_dir, dependencies):
     return i
 
   def f(i):
+    # This script is only for adding new binaries that are created as part of
+    # the component build.
+    ext = os.path.splitext(i)[1]
+    if ext not in ['.dll', '.so', '.dylib']:
+      return False
+
     # Check for execute access and strip directories. This gets rid of all the
     # phony rules.
     p = os.path.join(build_dir, i)