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/memory_usage.cc

@@ -12,14 +12,17 @@
 
 #if defined(WEBRTC_LINUX)
 #include <unistd.h>
-#include <cstdlib>
 #include <cstdio>
+#include <cstdlib>
 #include <cstring>
 #elif defined(WEBRTC_MAC)
 #include <mach/mach.h>
 #elif defined(WEBRTC_WIN)
+// clang-format off
+// clang formating would change include order.
 #include <windows.h>
-#include <psapi.h>
+#include <psapi.h> // must come after windows.h
+// clang-format on
 #endif
 
 #include "rtc_base/logging.h"