Remove renderer notifications of memory pressure.

chrome/browser/memory/tab_stats.h

Index: chrome/browser/memory/tab_stats.h
diff --git a/chrome/browser/memory/tab_stats.h b/chrome/browser/memory/tab_stats.h
index b2be60adab6deb973810bc1da484a2dd57c1aba8..38cdb0179680bc28159e4c0003bac1deba59d419 100644
--- a/chrome/browser/memory/tab_stats.h
+++ b/chrome/browser/memory/tab_stats.h
@@ -23,26 +23,31 @@ namespace memory {
 struct TabStats {
   TabStats();
   TabStats(const TabStats& other);
+  TabStats(TabStats&& other) noexcept;
   ~TabStats();
-  bool is_app;            // Browser window is an app.
-  bool is_internal_page;  // Internal page, such as NTP or Settings.
-  bool is_media;  // Playing audio, acessing cam/mic or mirroring display.
-  bool is_pinned;
-  bool is_selected;  // Selected in the currently active browser window.
-  bool is_discarded;
-  bool has_form_entry;  // User has entered text in a form.
-  int discard_count;
+
+  TabStats& operator=(const TabStats& other);
+
+  bool is_app = false;            // Browser window is an app.
+  bool is_internal_page = false;  // Internal page, such as NTP or Settings.
+  // Playing audio, accessing cam/mic or mirroring display.
+  bool is_media = false;
+  bool is_pinned = false;
+  bool is_selected = false;  // Selected in the currently active browser window.
+  bool is_discarded = false;
+  bool has_form_entry = false;  // User has entered text in a form.
+  int discard_count = 0;
   base::TimeTicks last_active;
   base::TimeTicks last_hidden;
-  content::RenderProcessHost* render_process_host;
-  base::ProcessHandle renderer_handle;
-  int child_process_host_id;
+  content::RenderProcessHost* render_process_host = nullptr;
+  base::ProcessHandle renderer_handle = 0;
+  int child_process_host_id = 0;
   base::string16 title;
 #if defined(OS_CHROMEOS)
-  int oom_score;
+  int oom_score = 0;
 #endif
-  int64_t tab_contents_id;  // Unique ID per WebContents.
-  bool is_auto_discardable;
+  int64_t tab_contents_id = 0;  // Unique ID per WebContents.
+  bool is_auto_discardable = true;
 };
 
 typedef std::vector<TabStats> TabStatsList;