Reformat the WebRTC code base

Running clang-format with chromium's style guide.

The goal is n-fold:
 * providing consistency and readability (that's what code guidelines are for)
 * preventing noise with presubmit checks and git cl format
 * building on the previous point: making it easier to automatically fix format issues
 * you name it

Please consider using git-hyper-blame to ignore this commit.

Bug: webrtc:9340
Change-Id: I694567c4cdf8cee2860958cfe82bfaf25848bb87
Reviewed-on: https://webrtc-review.googlesource.com/81185
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23660}

system_wrappers/source/clock.cc

@@ -223,7 +223,7 @@ Clock* Clock::GetRealTimeClock() {
 #elif defined(WEBRTC_POSIX)
   static UnixRealTimeClock clock;
   return &clock;
-#else  // defined(WEBRTC_POSIX)
+#else   // defined(WEBRTC_POSIX)
   return nullptr;
 #endif  // !defined(WEBRTC_WIN) || defined(WEBRTC_POSIX)
 }