PerformanceMonitor: UMA alert for high browser CPU usage.

chrome/chrome_browser.gypi

Index: chrome/chrome_browser.gypi
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index a561905cc6e998f8a4bf518d908d42c572dc3e36..6f77285687ba8d622c2e7e296144bb3d109f791b 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -1390,6 +1390,8 @@
         'browser/performance_monitor/performance_monitor.h',
         'browser/performance_monitor/performance_monitor_util.cc',
         'browser/performance_monitor/performance_monitor_util.h',
+        'browser/performance_monitor/process_metrics_history.cc',
+        'browser/performance_monitor/process_metrics_history.h',
         'browser/performance_monitor/startup_timer.cc',
         'browser/performance_monitor/startup_timer.h',
         'browser/platform_util.h',
@@ -2566,14 +2568,6 @@
         'browser/webdata/web_intents_table.cc',
         'browser/webdata/web_intents_table.h',
 
-        # These files are needed by performance_monitor.cc and this dependency
-        # should be removed (crbug.com/279660)
-        'test/base/test_switches.cc',
-        'test/base/test_switches.h',
-        'test/base/chrome_process_util.cc',
-        'test/base/chrome_process_util.h',
-        'test/base/chrome_process_util_mac.cc',
-
         # These files are generated by GRIT.
         '<(grit_out_dir)/grit/component_extension_resources_map.cc',
         '<(grit_out_dir)/grit/devtools_discovery_page_resources_map.cc',