[owners] Ensure OWNERS file ends with newline in //content

Some OWNERS file ends with a newline character, some don't. As
text editor tends to add newline at the end of text files when
saving, normalize all OWNERS files to end with a newline '\n'.

Bug: none
Change-Id: Ie9581a9296b5090e578976598c34d783c6797690
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2905540
Reviewed-by: Charlie Reis <creis@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#884941}

content/browser/metrics/OWNERS

@@ -1 +1 @@
-file://base/metrics/OWNERS
+file://base/metrics/OWNERS

content/browser/renderer_host/input/OWNERS

@@ -1,3 +1,3 @@
 dtapuska@chromium.org
 flackr@chromium.org
-bokan@chromium.org
+bokan@chromium.org

content/browser/resources/histograms/OWNERS

@@ -1 +1 @@
-asvitkine@chromium.org
+asvitkine@chromium.org

content/browser/tracing/OWNERS

@@ -1 +1 @@
-file://base/trace_event/OWNERS
+file://base/trace_event/OWNERS

content/common/download/OWNERS

@@ -1,2 +1,2 @@
 per-file *.mojom=set noparent
-per-file *.mojom=file://ipc/SECURITY_OWNERS
+per-file *.mojom=file://ipc/SECURITY_OWNERS

content/shell/common/OWNERS

@@ -5,4 +5,4 @@ per-file *.mojom=file://ipc/SECURITY_OWNERS
 per-file *_messages.cc=set noparent
 per-file *_messages.cc=file://ipc/SECURITY_OWNERS
 per-file *_param_traits*.*=set noparent
-per-file *_param_traits*.*=file://ipc/SECURITY_OWNERS
+per-file *_param_traits*.*=file://ipc/SECURITY_OWNERS