Revert "gclient_utils: buffer output as bytestrings in Annotated"

This reverts commit 5d284fdf48ab00a873e710c6ab76818d5b54d2cc.

Reason for revert: breaks buildbots, crbug.com/1011982

Original change's description:
> gclient_utils: buffer output as bytestrings in Annotated
> 
> In Python 3 byestrings and normal strings can't be concatenated.
> To fix this we buffer as bytestrings in the Annotated wrapper.
> We can't decode to a string because the output might come byte-by-byte, so it doesn't work with Unicode characters like ✔.
> 
> Also had to update gclient_test.py, where double-wrapping stdout with Annotated caused made output not work and include_zero=True working caused other unintended side-effects.
> 
> Example error from "fetch chromium":
> Traceback (most recent call last):
>   File "C:\Google\depot_tools\gclient_scm.py", line 1045, in _Clone
>     self._Run(clone_cmd, options, cwd=self._root_dir, retry=True,
>   File "C:\Google\depot_tools\gclient_scm.py", line 1370, in _Run
>     gclient_utils.CheckCallAndFilter(cmd, env=env, **kwargs)
>   File "C:\Google\depot_tools\gclient_utils.py", line 583, in CheckCallAndFilter
>     show_header_if_necessary(needs_header, attempt)
>   File "C:\Google\depot_tools\gclient_utils.py", line 533, in show_header_if_necessary
>     stdout_write(header.encode())
>   File "C:\Google\depot_tools\gclient_utils.py", line 391, in write
>     obj[0] += out
> TypeError: can only concatenate str (not "bytes") to str
> 
> Bug: 984182
> Change-Id: If7037d30e9faf524f2405258281f6e6cd0bcdcae
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1778745
> Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
> Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
> Auto-Submit: Raul Tambre <raul@tambre.ee>

TBR=dpranke@chromium.org,ehmaldonado@chromium.org,raul@tambre.ee

Change-Id: I5ea8d3249c58a3487996649a264bb5be059fe884
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 984182
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1845500
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
diff --git a/gclient_utils.py b/gclient_utils.py
index 2c38a3a..3a6bc1f 100644
--- a/gclient_utils.py
+++ b/gclient_utils.py
@@ -40,10 +40,8 @@
 
 if sys.version_info.major == 2:
   from cStringIO import StringIO
-  string_type = basestring
 else:
   from io import StringIO
-  string_type = str
 
 
 RETRY_MAX = 3
@@ -373,10 +371,6 @@
   def write(self, out):
     index = getattr(threading.currentThread(), 'index', 0)
     if not index and not self.__include_zero:
-      # Store as bytes to ensure Unicode characters get output correctly.
-      if isinstance(out, bytes):
-        out = out.decode('utf-8')
-
       # Unindexed threads aren't buffered.
       return self._wrapped.write(out)
 
@@ -386,32 +380,28 @@
       # Strings are immutable, requiring to keep a lock for the whole dictionary
       # otherwise. Using an array is faster than using a dummy object.
       if not index in self.__output_buffers:
-        obj = self.__output_buffers[index] = [b'']
+        obj = self.__output_buffers[index] = ['']
       else:
         obj = self.__output_buffers[index]
     finally:
       self.lock.release()
 
-    # Store as bytes to ensure Unicode characters get output correctly.
-    if isinstance(out, string_type):
-      out = out.encode('utf-8')
-
     # Continue lockless.
     obj[0] += out
     while True:
       # TODO(agable): find both of these with a single pass.
-      cr_loc = obj[0].find(b'\r')
-      lf_loc = obj[0].find(b'\n')
+      cr_loc = obj[0].find('\r')
+      lf_loc = obj[0].find('\n')
       if cr_loc == lf_loc == -1:
         break
       elif cr_loc == -1 or (lf_loc >= 0 and lf_loc < cr_loc):
-        line, remaining = obj[0].split(b'\n', 1)
+        line, remaining = obj[0].split('\n', 1)
         if line:
-          self._wrapped.write('%d>%s\n' % (index, line.decode('utf-8')))
+          self._wrapped.write('%d>%s\n' % (index, line))
       elif lf_loc == -1 or (cr_loc >= 0 and cr_loc < lf_loc):
-        line, remaining = obj[0].split(b'\r', 1)
+        line, remaining = obj[0].split('\r', 1)
         if line:
-          self._wrapped.write('%d>%s\r' % (index, line.decode('utf-8')))
+          self._wrapped.write('%d>%s\r' % (index, line))
       obj[0] = remaining
 
   def flush(self):
@@ -433,7 +423,7 @@
     # Don't keep the lock while writting. Will append \n when it shouldn't.
     for orphan in orphans:
       if orphan[1]:
-        self._wrapped.write('%d>%s\n' % (orphan[0], orphan[1].decode('utf-8')))
+        self._wrapped.write('%d>%s\n' % (orphan[0], orphan[1]))
     return self._wrapped.flush()