CrOS - Add free memory status widget to about:flags

We're working on memory consumption on ARM and it's useful to have realtime
feedback on system-wide memory consumption.  Also added pkasting's memory
purger as a menu command, fixed some comments, and fixed an include that was
confusing eclipse.

BUG=chromium-os:18564
TEST=Open about:flags and turn it on and off

Review URL: http://codereview.chromium.org/7548030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@95246 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 45 insertions, 4 deletions

diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 3416b43..26ec54f 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -4213,6 +4213,12 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_FLAGS_ENABLE_SHORTCUTS_PROVIDER_DESCRIPTION" desc=" Description of the 'Enable better ranking of previously selected shortcuts in omnibox' lab.">
         Remembers commonly selected autocomplete results based on the omnibox search term and offers those URLs the next time that same search term is typed.
       </message>      
+      <message name="IDS_FLAGS_MEMORY_WIDGET_NAME" desc="Name of the 'Show memory status' lab.">
+        Show memory status
+      </message>
+      <message name="IDS_FLAGS_MEMORY_WIDGET_DESCRIPTION" desc="Description of the 'Show memory status' lab.">
+        Shows the amount of free memory in the status area. Click on the menu for more information about system memory.
+      </message>      
       <message name="IDS_FLAGS_XSS_AUDITOR_NAME" desc="Description of the 'XSS Auditor' lab.">
         XSS Auditor
       </message>
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index f7e9dc8..7cbdf71 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -344,7 +344,18 @@ const Experiment kExperiments[] = {
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kEnableShortcutsProvider)
   },
-};
+  {
+    "memory-widget",
+    IDS_FLAGS_MEMORY_WIDGET_NAME,
+    IDS_FLAGS_MEMORY_WIDGET_DESCRIPTION,
+    kOsCrOS,
+#if defined(OS_CHROMEOS)
+    // This switch exists only on Chrome OS.
+    SINGLE_VALUE_TYPE(switches::kMemoryWidget)
+#else
+    SINGLE_VALUE_TYPE("")
+#endif
+  },};
 
 const Experiment* experiments = kExperiments;
 size_t num_experiments = arraysize(kExperiments);
diff --git a/chrome/browser/browser_about_handler.h b/chrome/browser/browser_about_handler.h
index c496beb..2779cc3 100644
--- a/chrome/browser/browser_about_handler.h
+++ b/chrome/browser/browser_about_handler.h
@@ -14,6 +14,7 @@
 
 #include "base/process.h"
 #include "base/stringprintf.h"
+#include "build/build_config.h"  // USE_TCMALLOC
 
 template <typename T> struct DefaultSingletonTraits;
 class GURL;
diff --git a/chrome/browser/chromeos/status/memory_menu_button.cc b/chrome/browser/chromeos/status/memory_menu_button.cc
index 4bdf9a1..606ebc1 100644
--- a/chrome/browser/chromeos/status/memory_menu_button.cc
+++ b/chrome/browser/chromeos/status/memory_menu_button.cc
@@ -7,6 +7,7 @@
 #include "base/process_util.h"  // GetSystemMemoryInfo
 #include "base/stringprintf.h"
 #include "chrome/browser/chromeos/status/status_area_host.h"
+#include "chrome/browser/memory_purger.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "views/widget/widget.h"
@@ -20,6 +21,7 @@ enum {
   MEM_BUFFERS_ITEM,
   MEM_CACHE_ITEM,
   SHMEM_ITEM,
+  PURGE_MEMORY_ITEM,
 };
 
 }  // namespace
@@ -78,16 +80,31 @@ std::wstring MemoryMenuButton::GetLabel(int id) const {
       return StringPrintf(L"%d MB cache", mem_cache_ / 1024);
     case SHMEM_ITEM:
       return StringPrintf(L"%d MB shmem", shmem_ / 1024);
+    case PURGE_MEMORY_ITEM:
+      return L"Purge memory";
     default:
       return std::wstring();
   }
 }
 
 bool MemoryMenuButton::IsCommandEnabled(int id) const {
-  return false;
+  switch (id) {
+    case PURGE_MEMORY_ITEM:
+      return true;
+    default:
+      return false;
+  }
 }
 
 void MemoryMenuButton::ExecuteCommand(int id) {
+  switch (id) {
+    case PURGE_MEMORY_ITEM:
+      MemoryPurger::PurgeAll();
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
 }
 
 int MemoryMenuButton::horizontal_padding() {
@@ -124,7 +141,9 @@ void MemoryMenuButton::EnsureMenu() {
   menu_->AppendDelegateMenuItem(MEM_BUFFERS_ITEM);
   menu_->AppendDelegateMenuItem(MEM_CACHE_ITEM);
   menu_->AppendDelegateMenuItem(SHMEM_ITEM);
-  // TODO(jamescook): Add items to run memory_purger, dump heap profiles.
+  // TODO(jamescook): Dump heap profiles?
+  menu_->AppendSeparator();
+  menu_->AppendDelegateMenuItem(PURGE_MEMORY_ITEM);
 }
 
 }  // namespace chromeos
diff --git a/chrome/browser/chromeos/status/memory_menu_button.h b/chrome/browser/chromeos/status/memory_menu_button.h
index c399df7..feddcac 100644
--- a/chrome/browser/chromeos/status/memory_menu_button.h
+++ b/chrome/browser/chromeos/status/memory_menu_button.h
@@ -37,7 +37,7 @@ class MemoryMenuButton : public StatusAreaButton,
   void UpdateText();
 
  protected:
-  virtual int horizontal_padding();
+  virtual int horizontal_padding() OVERRIDE;
 
  private:
   // views::ViewMenuDelegate implementation.
diff --git a/chrome/browser/memory_purger.h b/chrome/browser/memory_purger.h
index b86172d..667b530 100644
--- a/chrome/browser/memory_purger.h
+++ b/chrome/browser/memory_purger.h
@@ -5,6 +5,10 @@
 // MemoryPurger provides static APIs to purge as much memory as possible from
 // all processes.  These can be hooked to various signals to try and balance
 // memory consumption, speed, page swapping, etc.
+//
+// This was implemented in an attempt to speed up suspend-to-disk by throwing
+// away any cached data that can be recomputed.  Memory use will rapidly
+// re-expand after this purge is run.
 
 #ifndef CHROME_BROWSER_MEMORY_PURGER_H_
 #define CHROME_BROWSER_MEMORY_PURGER_H_