PRESUBMIT: Improve PyLint check and add GN format check.

Add pylintrc file based on
https://code.google.com/p/chromium/codesearch#chromium/src/tools/perf/pylintrc
bit tightened up quite a bit (the one in depot_tools is far
more relaxed).

Remove a few excluded directories from pylint check and fixed/
suppressed all warnings generated.

Add GN format check + formatted all GN files using 'gn format'.
Cleanup redundant rules in tools/PRESUBMIT.py

TESTED=Ran 'git cl presubmit -vv', fixed the PyLint violations.
Ran it again with a modification in webrtc/build/webrtc.gni, formatted
all the GN files and ran it again.

R=henrika@webrtc.org, phoglund@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/50069004

Cr-Commit-Position: refs/heads/master@{#9274}
diff --git a/webrtc/BUILD.gn b/webrtc/BUILD.gn
index 45b05b6..6c6c23c 100644
--- a/webrtc/BUILD.gn
+++ b/webrtc/BUILD.gn
@@ -20,13 +20,12 @@
     defines += [ "WEBRTC_MOZILLA_BUILD" ]
   }
   if (build_with_chromium) {
-    defines = [
-      "WEBRTC_CHROMIUM_BUILD",
-    ]
+    defines = [ "WEBRTC_CHROMIUM_BUILD" ]
     include_dirs = [
       # overrides must be included first as that is the mechanism for
       # selecting the override headers in Chromium.
       "overrides",
+
       # Allow includes to be prefixed with webrtc/ in case it is not an
       # immediate subdirectory of the top-level.
       "..",
@@ -73,6 +72,7 @@
 
   if (rtc_have_dbus_glib) {
     defines += [ "HAVE_DBUS_GLIB" ]
+
     # TODO(kjellander): Investigate this, it seems like include <dbus/dbus.h>
     # is still not found even if the execution of
     # build/config/linux/pkg-config.py dbus-glib-1 returns correct include
@@ -93,6 +93,7 @@
       if (current_cpu != "arm64" || !is_android) {
         cflags = [
           "-Wextra",
+
           # We need to repeat some flags from Chromium"s common.gypi
           # here that get overridden by -Wextra.
           "-Wno-unused-parameter",
@@ -101,6 +102,7 @@
         ]
         cflags_cc = [
           "-Wnon-virtual-dtor",
+
           # This is enabled for clang; enable for gcc as well.
           "-Woverloaded-virtual",
         ]
@@ -172,7 +174,7 @@
   ]
 
   configs += [ ":common_config" ]
-  public_configs = [ ":common_inherited_config"]
+  public_configs = [ ":common_inherited_config" ]
 
   deps = [
     ":webrtc_common",
@@ -199,8 +201,8 @@
 
   if (build_with_chromium) {
     deps += [
-    "modules/video_capture",
-    "modules/video_render",
+      "modules/video_capture",
+      "modules/video_render",
     ]
   }
 }
@@ -221,8 +223,8 @@
   sources = [
     "common_types.cc",
     "common_types.h",
-    "config.h",
     "config.cc",
+    "config.h",
     "engine_configurations.h",
     "typedefs.h",
   ]