Revert 232274 "Reland "Enable SysInfo::AmountOfPhysicalMemory to..."

Broke all linux dbg layout tests (again):
http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20%28dbg%29/builds/14495

> Reland "Enable SysInfo::AmountOfPhysicalMemory to be called from within the Linux Sandbox"
> 
> Trigger caching of SysInfo::AmountOfPhysicalMemory in PreSandboxInit() to enable
> it to be called by the renderer process after the sandbox is sealed.
> 
> BUG=312241
> 
> Review URL: https://codereview.chromium.org/52403002

TBR=rmcilroy@chromium.org

Review URL: https://codereview.chromium.org/54923005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232282 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 23 insertions, 47 deletions

diff --git a/base/sys_info_linux.cc b/base/sys_info_linux.cc
index fe242b0..acc4771 100644
--- a/base/sys_info_linux.cc
+++ b/base/sys_info_linux.cc
@@ -7,7 +7,6 @@
 #include <limits>
 
 #include "base/file_util.h"
-#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 
@@ -23,64 +22,41 @@ int64 AmountOfMemory(int pages_name) {
   return static_cast<int64>(pages) * page_size;
 }
 
-size_t MaxSharedMemorySize() {
-  std::string contents;
-  base::ReadFileToString(base::FilePath("/proc/sys/kernel/shmmax"), &contents);
-  DCHECK(!contents.empty());
-  if (!contents.empty() && contents[contents.length() - 1] == '\n') {
-    contents.erase(contents.length() - 1);
-  }
-
-  int64 limit;
-  if (!base::StringToInt64(contents, &limit)) {
-    limit = 0;
-  }
-  if (limit < 0 ||
-      static_cast<uint64>(limit) > std::numeric_limits<size_t>::max()) {
-    limit = 0;
-  }
-  DCHECK(limit > 0);
-  return static_cast<size_t>(limit);
-}
-
-class LazySysInfo {
- public:
-  LazySysInfo()
-      : kPhysicalMemory_(AmountOfMemory(_SC_PHYS_PAGES)),
-        kMaxSharedMemorySize_(MaxSharedMemorySize()) { }
-
-  ~LazySysInfo() { }
-
-  int64 physical_memory() { return kPhysicalMemory_; }
-  size_t max_shared_memory_size() { return kMaxSharedMemorySize_; }
-
- private:
-  const int64 kPhysicalMemory_;
-  const size_t kMaxSharedMemorySize_;
-
-  DISALLOW_COPY_AND_ASSIGN(LazySysInfo);
-};
-
-base::LazyInstance<LazySysInfo>::Leaky
-    g_lazy_sys_info = LAZY_INSTANCE_INITIALIZER;
-
 }  // namespace
 
 namespace base {
 
 // static
-int64 SysInfo::AmountOfAvailablePhysicalMemory() {
-  return AmountOfMemory(_SC_AVPHYS_PAGES);
+int64 SysInfo::AmountOfPhysicalMemory() {
+  return AmountOfMemory(_SC_PHYS_PAGES);
 }
 
 // static
-int64 SysInfo::AmountOfPhysicalMemory() {
-  return g_lazy_sys_info.Get().physical_memory();
+int64 SysInfo::AmountOfAvailablePhysicalMemory() {
+  return AmountOfMemory(_SC_AVPHYS_PAGES);
 }
 
 // static
 size_t SysInfo::MaxSharedMemorySize() {
-  return g_lazy_sys_info.Get().max_shared_memory_size();
+  static int64 limit;
+  static bool limit_valid = false;
+  if (!limit_valid) {
+    std::string contents;
+    ReadFileToString(FilePath("/proc/sys/kernel/shmmax"), &contents);
+    DCHECK(!contents.empty());
+    if (!contents.empty() && contents[contents.length() - 1] == '\n') {
+      contents.erase(contents.length() - 1);
+    }
+    if (base::StringToInt64(contents, &limit)) {
+      DCHECK(limit >= 0);
+      DCHECK(static_cast<uint64>(limit) <= std::numeric_limits<size_t>::max());
+      limit_valid = true;
+    } else {
+      NOTREACHED();
+      return 0;
+    }
+  }
+  return static_cast<size_t>(limit);
 }
 
 // static