gpu: Print error when command buffer function can't be parsed.

Useful for figuring out what went wrong.

R=piman
BUG=NONE

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: Iee7ff46f8550131b6090085decef8dc21a53a9b1
Reviewed-on: https://chromium-review.googlesource.com/737063Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: Sunny Sachanandani <sunnyps@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512711}

gpu/command_buffer/build_gles2_cmd_buffer.py

@@ -9949,7 +9949,9 @@ def CreateArg(arg_string):
 class GLGenerator(object):
   """A class to generate GL command buffers."""
 
-  _function_re = re.compile(r'GL_APICALL(.*?)GL_APIENTRY (.*?) \((.*?)\);')
+  _whitespace_re = re.compile(r'^\w*$')
+  _comment_re = re.compile(r'^//.*$')
+  _function_re = re.compile(r'^GL_APICALL(.*?)GL_APIENTRY (.*?) \((.*?)\);$')
 
   def __init__(self, verbose):
     self.original_functions = []
@@ -9996,6 +9998,8 @@ class GLGenerator(object):
     with open(filename, "r") as f:
       functions = f.read()
     for line in functions.splitlines():
+      if self._whitespace_re.match(line) or self._comment_re.match(line):
+        continue
       match = self._function_re.match(line)
       if match:
         func_name = match.group(2)[2:]
@@ -10033,6 +10037,9 @@ class GLGenerator(object):
               self.AddFunction(f)
           else:
             self.AddFunction(f)
+      else:
+        self.Error("Could not parse function: %s using regex: %s" %
+                   (line, self._function_re.pattern))
 
     self.Log("Auto Generated Functions    : %d" %
              len([f for f in self.functions if f.can_auto_generate or