Replace Atomic32 with webrtc/base/atomicops.h.

webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc

Index: webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc b/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
index e6087f112396027226763a6353d7e4adffa33ee3..dc0935a4a36ea3f7da43edee2b753c360f8b4e6a 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
@@ -12,6 +12,7 @@
 
 #include <assert.h>
 
+#include "webrtc/base/atomicops.h"
 #include "webrtc/modules/desktop_capture/desktop_capture_options.h"
 #include "webrtc/modules/desktop_capture/desktop_frame.h"
 #include "webrtc/modules/desktop_capture/desktop_frame_win.h"
@@ -33,7 +34,7 @@ static LPCTSTR kHostWindowName = L"MagnifierHost";
 static LPCTSTR kMagnifierWindowClass = L"Magnifier";
 static LPCTSTR kMagnifierWindowName = L"MagnifierWindow";
 
-Atomic32 ScreenCapturerWinMagnifier::tls_index_(TLS_OUT_OF_INDEXES);
+volatile int ScreenCapturerWinMagnifier::tls_index_(TLS_OUT_OF_INDEXES);
 
 ScreenCapturerWinMagnifier::ScreenCapturerWinMagnifier(
     rtc::scoped_ptr<ScreenCapturer> fallback_capturer)
@@ -236,11 +237,11 @@ BOOL ScreenCapturerWinMagnifier::OnMagImageScalingCallback(
     RECT unclipped,
     RECT clipped,
     HRGN dirty) {
-  assert(tls_index_.Value() != TLS_OUT_OF_INDEXES);
+  assert(rtc::AtomicOps::AcquireLoad(&tls_index_) != TLS_OUT_OF_INDEXES);
 
   ScreenCapturerWinMagnifier* owner =
       reinterpret_cast<ScreenCapturerWinMagnifier*>(
-          TlsGetValue(tls_index_.Value()));
+          TlsGetValue(rtc::AtomicOps::AcquireLoad(&tls_index_)));
 
   owner->OnCaptured(srcdata, srcheader);
 
@@ -369,16 +370,19 @@ bool ScreenCapturerWinMagnifier::InitializeMagnifier() {
     }
   }
 
-  if (tls_index_.Value() == TLS_OUT_OF_INDEXES) {
+  if (rtc::AtomicOps::AcquireLoad(&tls_index_) == TLS_OUT_OF_INDEXES) {
     // More than one threads may get here at the same time, but only one will
-    // write to tls_index_ using CompareExchange.
+    // write to tls_index_ using CompareAndSwap.
     DWORD new_tls_index = TlsAlloc();
-    if (!tls_index_.CompareExchange(new_tls_index, TLS_OUT_OF_INDEXES))
+    if (rtc::AtomicOps::CompareAndSwap(&tls_index_, TLS_OUT_OF_INDEXES,
+                                       new_tls_index) != TLS_OUT_OF_INDEXES) {
+      // Another thread allocated TLS before us, remove additional allocation.
       TlsFree(new_tls_index);
+    }
   }
 
-  assert(tls_index_.Value() != TLS_OUT_OF_INDEXES);
-  TlsSetValue(tls_index_.Value(), this);
+  assert(rtc::AtomicOps::AcquireLoad(&tls_index_) != TLS_OUT_OF_INDEXES);
+  TlsSetValue(rtc::AtomicOps::AcquireLoad(&tls_index_), this);
 
   magnifier_initialized_ = true;
   return true;