Remove trailing whitespace.

Also adds a presubmit to prevent adding trailing whitespace to source
code in the future.

Change-Id: I41a4df81487f6f00aa19b188f0cac6a3377efde6
Reviewed-on: https://skia-review.googlesource.com/57380
Reviewed-by: Ravi Mistry <rmistry@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
diff --git a/tools/merge_static_libs.py b/tools/merge_static_libs.py
index 842be18..a32c3a5 100755
--- a/tools/merge_static_libs.py
+++ b/tools/merge_static_libs.py
@@ -15,7 +15,7 @@
 
 def MergeLibs(in_libs, out_lib):
   """ Merges multiple static libraries into one.
-  
+
   in_libs: list of paths to static libraries to be merged
   out_lib: path to the static library which will be created from in_libs
   """
@@ -38,12 +38,12 @@
       proc.wait()
       if proc.poll() == 0:
         # The static library is non-thin, and we extracted objects
-        for object in current_objects:
-          objects.append(os.path.abspath(object))
+        for obj in current_objects:
+          objects.append(os.path.abspath(obj))
       elif 'thin archive' in proc.communicate()[0]:
         # The static library is thin, so it contains the paths to its objects
-        for object in current_objects:
-          objects.append(object)
+        for obj in current_objects:
+          objects.append(obj)
       else:
         raise Exception('Failed to extract objects from %s.' % in_lib)
     os.chdir(curdir)