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/callback_unittest.cc

@@ -19,9 +19,15 @@ namespace rtc {
 namespace {
 
 void f() {}
-int g() { return 42; }
-int h(int x) { return x * x; }
-void i(int& x) { x *= x; }  // NOLINT: Testing refs
+int g() {
+  return 42;
+}
+int h(int x) {
+  return x * x;
+}
+void i(int& x) {
+  x *= x;
+}  // NOLINT: Testing refs
 
 struct BindTester {
   int a() { return 24; }