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}

rtc_base/strings/string_builder.h

@@ -55,7 +55,7 @@ class SimpleStringBuilder {
   // compatibility reasons.
   size_t size() const { return size_; }
 
-  // Allows appending a printf style formatted string.
+// Allows appending a printf style formatted string.
 #if defined(__GNUC__)
   __attribute__((__format__(__printf__, 2, 3)))
 #endif