bootstat: Refactor init/utils/boot_clock into base/chrono_utils.

Use this for bootstat and init. This replaces the custom uptime parser in
bootstat.

This is a reland of aosp/338325 with a stubbed implementation for Darwin.

This change also has clang_format fixes (automatic).

Bug: 34352037
Test: chrono_utils_test
Change-Id: I72a62a3ca1ccfc0a4ccc6294ff1776c263144686
diff --git a/base/Android.bp b/base/Android.bp
index 7b1dc8e..121da42 100644
--- a/base/Android.bp
+++ b/base/Android.bp
@@ -42,24 +42,36 @@
             srcs: [
                 "errors_unix.cpp",
                 "properties.cpp",
+                "chrono_utils.cpp",
             ],
             cppflags: ["-Wexit-time-destructors"],
             sanitize: {
                 misc_undefined: ["integer"],
             },
+
         },
         darwin: {
-            srcs: ["errors_unix.cpp"],
+            srcs: [
+                "chrono_utils.cpp",
+                "errors_unix.cpp",
+            ],
             cppflags: ["-Wexit-time-destructors"],
         },
         linux_bionic: {
-            srcs: ["errors_unix.cpp"],
+            srcs: [
+                "chrono_utils.cpp",
+                "errors_unix.cpp",
+            ],
             cppflags: ["-Wexit-time-destructors"],
             enabled: true,
         },
         linux: {
-            srcs: ["errors_unix.cpp"],
+            srcs: [
+                "chrono_utils.cpp",
+                "errors_unix.cpp",
+            ],
             cppflags: ["-Wexit-time-destructors"],
+            host_ldlibs: ["-lrt"],
         },
         windows: {
             srcs: [
@@ -92,11 +104,18 @@
     ],
     target: {
         android: {
-            srcs: ["properties_test.cpp"],
+            srcs: [
+                "chrono_utils_test.cpp",
+                "properties_test.cpp"
+            ],
             sanitize: {
                 misc_undefined: ["integer"],
             },
         },
+        linux: {
+            srcs: ["chrono_utils_test.cpp"],
+            host_ldlibs: ["-lrt"],
+        },
         windows: {
             srcs: ["utf8_test.cpp"],
             enabled: true,