Revert of Change WebContents::last_active_time_ to Time instead of Timeticks.

chrome/browser/android/dev_tools_discovery_provider_android.cc

Index: chrome/browser/android/dev_tools_discovery_provider_android.cc
diff --git a/chrome/browser/android/dev_tools_discovery_provider_android.cc b/chrome/browser/android/dev_tools_discovery_provider_android.cc
index 5a2eb32ad49334d1a4da93dac77a43e3e8126f59..08d3e5579a1e88229adf43448ecfa097822fdd17 100644
--- a/chrome/browser/android/dev_tools_discovery_provider_android.cc
+++ b/chrome/browser/android/dev_tools_discovery_provider_android.cc
@@ -65,7 +65,9 @@
     return favicon_url_;
   }
 
-  base::Time GetLastActiveTime() const override { return last_active_time_; }
+  base::TimeTicks GetLastActivityTime() const override {
+    return last_activity_time_;
+  }
 
   std::string GetId() const override {
     return base::IntToString(tab_id_);
@@ -132,7 +134,8 @@
         title_(base::UTF16ToUTF8(web_contents->GetTitle())),
         url_(web_contents->GetURL()),
         favicon_url_(CalculateFaviconURL()),
-        last_active_time_(web_contents->GetLastActiveTime()) {}
+        last_activity_time_(web_contents->GetLastActiveTime()) {
+  }
 
   TabDescriptor(int tab_id, const base::string16& title, const GURL& url)
       : tab_id_(tab_id),
@@ -188,7 +191,7 @@
   const std::string title_;
   const GURL url_;
   const GURL favicon_url_;
-  const base::Time last_active_time_;
+  const base::TimeTicks last_activity_time_;
 
   DISALLOW_COPY_AND_ASSIGN(TabDescriptor);
 };